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/getchar.h

@@ -0,0 +1,77 @@
+#ifndef NEOVIM_GETCHAR_H
+#define NEOVIM_GETCHAR_H
+/* getchar.c */
+void free_buff __ARGS((struct buffheader *buf));
+char_u *get_recorded __ARGS((void));
+char_u *get_inserted __ARGS((void));
+int stuff_empty __ARGS((void));
+void typeahead_noflush __ARGS((int c));
+void flush_buffers __ARGS((int flush_typeahead));
+void ResetRedobuff __ARGS((void));
+void CancelRedo __ARGS((void));
+void saveRedobuff __ARGS((void));
+void restoreRedobuff __ARGS((void));
+void AppendToRedobuff __ARGS((char_u *s));
+void AppendToRedobuffLit __ARGS((char_u *str, int len));
+void AppendCharToRedobuff __ARGS((int c));
+void AppendNumberToRedobuff __ARGS((long n));
+void stuffReadbuff __ARGS((char_u *s));
+void stuffReadbuffLen __ARGS((char_u *s, long len));
+void stuffReadbuffSpec __ARGS((char_u *s));
+void stuffcharReadbuff __ARGS((int c));
+void stuffnumReadbuff __ARGS((long n));
+int start_redo __ARGS((long count, int old_redo));
+int start_redo_ins __ARGS((void));
+void stop_redo_ins __ARGS((void));
+int ins_typebuf __ARGS((char_u *str, int noremap, int offset, int nottyped,
+                        int silent));
+void ins_char_typebuf __ARGS((int c));
+int typebuf_changed __ARGS((int tb_change_cnt));
+int typebuf_typed __ARGS((void));
+int typebuf_maplen __ARGS((void));
+void del_typebuf __ARGS((int len, int offset));
+int alloc_typebuf __ARGS((void));
+void free_typebuf __ARGS((void));
+int save_typebuf __ARGS((void));
+void save_typeahead __ARGS((tasave_T *tp));
+void restore_typeahead __ARGS((tasave_T *tp));
+void openscript __ARGS((char_u *name, int directly));
+void close_all_scripts __ARGS((void));
+int using_script __ARGS((void));
+void before_blocking __ARGS((void));
+void updatescript __ARGS((int c));
+int vgetc __ARGS((void));
+int safe_vgetc __ARGS((void));
+int plain_vgetc __ARGS((void));
+int vpeekc __ARGS((void));
+int vpeekc_nomap __ARGS((void));
+int vpeekc_any __ARGS((void));
+int char_avail __ARGS((void));
+void vungetc __ARGS((int c));
+int inchar __ARGS((char_u *buf, int maxlen, long wait_time, int tb_change_cnt));
+int fix_input_buffer __ARGS((char_u *buf, int len, int script));
+int input_available __ARGS((void));
+int do_map __ARGS((int maptype, char_u *arg, int mode, int abbrev));
+int get_map_mode __ARGS((char_u **cmdp, int forceit));
+void map_clear __ARGS((char_u *cmdp, char_u *arg, int forceit, int abbr));
+void map_clear_int __ARGS((buf_T *buf, int mode, int local, int abbr));
+char_u *map_mode_to_chars __ARGS((int mode));
+int map_to_exists __ARGS((char_u *str, char_u *modechars, int abbr));
+int map_to_exists_mode __ARGS((char_u *rhs, int mode, int abbr));
+char_u *set_context_in_map_cmd __ARGS((expand_T *xp, char_u *cmd, char_u *arg,
+                                       int forceit, int isabbrev, int isunmap,
+                                       cmdidx_T cmdidx));
+int ExpandMappings __ARGS((regmatch_T *regmatch, int *num_file, char_u ***file));
+int check_abbr __ARGS((int c, char_u *ptr, int col, int mincol));
+char_u *vim_strsave_escape_csi __ARGS((char_u *p));
+void vim_unescape_csi __ARGS((char_u *p));
+int makemap __ARGS((FILE *fd, buf_T *buf));
+int put_escstr __ARGS((FILE *fd, char_u *strstart, int what));
+void check_map_keycodes __ARGS((void));
+char_u *check_map __ARGS((char_u *keys, int mode, int exact, int ign_mod,
+                          int abbr, mapblock_T **mp_ptr,
+                          int *local_ptr));
+void init_mappings __ARGS((void));
+void add_map __ARGS((char_u *map, int mode));
+/* vim: set ft=c : */
+#endif /* NEOVIM_GETCHAR_H */