Introduce nvim namespace: Move files.

Move files from src/ to src/nvim/.
- src/nvim/ becomes the new root dir for nvim executable sources.
- src/libnvim/ is planned to become root dir of the neovim library.

src/nvim/version_defs.h

@@ -0,0 +1,47 @@
+#ifndef NEOVIM_VERSION_DEFS_H
+#define NEOVIM_VERSION_DEFS_H
+
+/*
+ * VIM - Vi IMproved		by Bram Moolenaar
+ *
+ * Do ":help uganda"  in Vim to read copying and usage conditions.
+ * Do ":help credits" in Vim to see a list of people who contributed.
+ */
+
+/*
+ * Define the version number, name, etc.
+ * The patchlevel is in included_patches[], in version.c.
+ *
+ * This doesn't use string concatenation, some compilers don't support it.
+ */
+
+#define VIM_VERSION_MAJOR                7
+#define VIM_VERSION_MAJOR_STR           "7"
+#define VIM_VERSION_MINOR                4
+#define VIM_VERSION_MINOR_STR           "4"
+#define VIM_VERSION_100     (VIM_VERSION_MAJOR * 100 + VIM_VERSION_MINOR)
+
+#define VIM_VERSION_BUILD                280
+#define VIM_VERSION_BUILD_BCD           0x118
+#define VIM_VERSION_BUILD_STR           "280"
+#define VIM_VERSION_PATCHLEVEL           0
+#define VIM_VERSION_PATCHLEVEL_STR      "0"
+/* Used by MacOS port should be one of: development, alpha, beta, final */
+#define VIM_VERSION_RELEASE             development
+
+/*
+ * VIM_VERSION_NODOT is used for the runtime directory name.
+ * VIM_VERSION_SHORT is copied into the swap file (max. length is 6 chars).
+ * VIM_VERSION_MEDIUM is used for the startup-screen.
+ * VIM_VERSION_LONG is used for the ":version" command and "Vim -h".
+ */
+#define VIM_VERSION_NODOT       "vim74"
+#define VIM_VERSION_SHORT       "7.4"
+#define VIM_VERSION_MEDIUM      "7.4"
+#define VIM_VERSION_LONG        "VIM - Vi IMproved 7.4 (2014)"
+#define VIM_VERSION_LONG_DATE   "VIM - Vi IMproved 7.4 (2014, compiled "
+
+/* Displayed on splash screen. */
+#define MODIFIED_BY "the Neovim contributors."
+
+#endif  // NEOVIM_VERSION_DEFS_H