Removes 'proto' dir

See #137 for the issue.

Every header in the proto directory was:

* Given include guards in the form

    #ifndef NEOVIM_FILENAME_H
    #define NEOVIM_FILENAME_H
        ...
    #endif /* NEOVIM_FILENAM_H */

* Renamed from *.pro -> *.h
* Moved from src/proto/ to src/

This would have caused conficts with some existing headers in src/;
rather than merge these conflicts now (which is a whole other can of
worms involving multiple and conditional inclusion), any header in src/
with a conflicting name was renamed from *.h -> *_defs.h (which may or
may not actually describe its purpose, the change is purely a
namespacing issue).

Once all of these changes were made a script was developed to determine
what #includes needed to be added to each source file to describe its
dependencies and allow it to compile; because the script is so short
and I'll just list it here:

    #! /bin/bash

    cd $(dirname $0)

    # Scrapes `make` output for provided error messages and outputs #includes
    # needed to resolve them.
    #   $1 : part of the clang error message between filename and identifier
    list_missing_includes() {
        for file_missing_pair in $(CC=clang make 2>&1 >/dev/null | sed -n "s/\/\(.*\.[hc]\).*$1.*'\(.*\)'.*/\1:\2/p"); do
            fields=(${file_missing_pair//:/ })
            source_file=${fields[0]}
            missing_func=${fields[1]}
            # Try to find the declaration of the missing function.
            echo $(basename $source_file) \
                \#include \"$(grep -r "\b$missing_func __ARGS" | sed -n "s/.*\/\(.*\)\:.*/\1/p")\"
        # Remove duplicates
        done | sort | uniq
    }

    echo "Finding missing function prototypes..."
    list_missing_includes "implicit declaration of function"
    echo "Finding missing identifier declarations..."
    list_missing_includes "use of undeclared identifier"

Each list of required headers was added by hand in the following format:

    #include "vim.h"
    #include "*_defs.h"
    #include "filename.h"
    /* All other includes in same module here, in alphabetical order. */
    /* All includes from other modules (e.g. "os/*.h") here in alphabetical
     * order. */

src/window.h

@@ -0,0 +1,96 @@
+#ifndef NEOVIM_WINDOW_H
+#define NEOVIM_WINDOW_H
+/* window.c */
+void do_window __ARGS((int nchar, long Prenum, int xchar));
+int win_split __ARGS((int size, int flags));
+int win_split_ins __ARGS((int size, int flags, win_T *new_wp, int dir));
+int win_valid __ARGS((win_T *win));
+int win_count __ARGS((void));
+int make_windows __ARGS((int count, int vertical));
+void win_move_after __ARGS((win_T *win1, win_T *win2));
+void win_equal __ARGS((win_T *next_curwin, int current, int dir));
+void close_windows __ARGS((buf_T *buf, int keep_curwin));
+int one_window __ARGS((void));
+int win_close __ARGS((win_T *win, int free_buf));
+void win_close_othertab __ARGS((win_T *win, int free_buf, tabpage_T *tp));
+void win_free_all __ARGS((void));
+win_T *winframe_remove __ARGS((win_T *win, int *dirp, tabpage_T *tp));
+void close_others __ARGS((int message, int forceit));
+void curwin_init __ARGS((void));
+void win_init_empty __ARGS((win_T *wp));
+int win_alloc_first __ARGS((void));
+void win_alloc_aucmd_win __ARGS((void));
+void win_init_size __ARGS((void));
+void free_tabpage __ARGS((tabpage_T *tp));
+int win_new_tabpage __ARGS((int after));
+int may_open_tabpage __ARGS((void));
+int make_tabpages __ARGS((int maxcount));
+int valid_tabpage __ARGS((tabpage_T *tpc));
+tabpage_T *find_tabpage __ARGS((int n));
+int tabpage_index __ARGS((tabpage_T *ftp));
+void goto_tabpage __ARGS((int n));
+void goto_tabpage_tp __ARGS((tabpage_T *tp, int trigger_enter_autocmds,
+                             int trigger_leave_autocmds));
+void goto_tabpage_win __ARGS((tabpage_T *tp, win_T *wp));
+void tabpage_move __ARGS((int nr));
+void win_goto __ARGS((win_T *wp));
+win_T *win_find_nr __ARGS((int winnr));
+tabpage_T *win_find_tabpage __ARGS((win_T *win));
+void win_enter __ARGS((win_T *wp, int undo_sync));
+win_T *buf_jump_open_win __ARGS((buf_T *buf));
+win_T *buf_jump_open_tab __ARGS((buf_T *buf));
+void win_append __ARGS((win_T *after, win_T *wp));
+void win_remove __ARGS((win_T *wp, tabpage_T *tp));
+int win_alloc_lines __ARGS((win_T *wp));
+void win_free_lsize __ARGS((win_T *wp));
+void shell_new_rows __ARGS((void));
+void shell_new_columns __ARGS((void));
+void win_size_save __ARGS((garray_T *gap));
+void win_size_restore __ARGS((garray_T *gap));
+int win_comp_pos __ARGS((void));
+void win_setheight __ARGS((int height));
+void win_setheight_win __ARGS((int height, win_T *win));
+void win_setwidth __ARGS((int width));
+void win_setwidth_win __ARGS((int width, win_T *wp));
+void win_setminheight __ARGS((void));
+void win_drag_status_line __ARGS((win_T *dragwin, int offset));
+void win_drag_vsep_line __ARGS((win_T *dragwin, int offset));
+void win_new_height __ARGS((win_T *wp, int height));
+void win_new_width __ARGS((win_T *wp, int width));
+void win_comp_scroll __ARGS((win_T *wp));
+void command_height __ARGS((void));
+void last_status __ARGS((int morewin));
+int tabline_height __ARGS((void));
+char_u *grab_file_name __ARGS((long count, linenr_T *file_lnum));
+char_u *file_name_at_cursor __ARGS((int options, long count,
+                                    linenr_T *file_lnum));
+char_u *file_name_in_line __ARGS((char_u *line, int col, int options,
+                                  long count, char_u *rel_fname,
+                                  linenr_T *file_lnum));
+char_u *find_file_name_in_path __ARGS((char_u *ptr, int len, int options,
+                                       long count,
+                                       char_u *rel_fname));
+int path_with_url __ARGS((char_u *fname));
+int vim_isAbsName __ARGS((char_u *name));
+int vim_FullName __ARGS((char_u *fname, char_u *buf, int len, int force));
+int min_rows __ARGS((void));
+int only_one_window __ARGS((void));
+void check_lnums __ARGS((int do_curwin));
+void make_snapshot __ARGS((int idx));
+void restore_snapshot __ARGS((int idx, int close_curwin));
+int switch_win __ARGS((win_T **save_curwin, tabpage_T **save_curtab, win_T *win,
+                       tabpage_T *tp,
+                       int no_display));
+void restore_win __ARGS((win_T *save_curwin, tabpage_T *save_curtab,
+                         int no_display));
+void switch_buffer __ARGS((buf_T **save_curbuf, buf_T *buf));
+void restore_buffer __ARGS((buf_T *save_curbuf));
+int win_hasvertsplit __ARGS((void));
+int match_add __ARGS((win_T *wp, char_u *grp, char_u *pat, int prio, int id));
+int match_delete __ARGS((win_T *wp, int id, int perr));
+void clear_matches __ARGS((win_T *wp));
+matchitem_T *get_match __ARGS((win_T *wp, int id));
+int get_win_number __ARGS((win_T *wp, win_T *first_win));
+int get_tab_number __ARGS((tabpage_T *tp));
+/* vim: set ft=c : */
+#endif /* NEOVIM_WINDOW_H */