MsgPack-RPC dispatch based on function array lookup #864

This simplifies the generated msgpack_rpc_dispatch() function, separates the
code for each RPC method more clearly and allows easy implementation of
alternative dispatching methods (e.g. string method id dispatch).
cmake: upgrade libuv 0.11.23 -> 0.11.26 #911

Fixes some bugs and increase the performance of uv_hrtime() on OSX, which
reduces its prominence in performance traces. This allows us to better see
what's really causing slowness.

ref:
- https://github.com/neovim/neovim/issues/868
- https://github.com/joyent/libuv/pull/1325
- https://github.com/joyent/libuv/releases
Add vim_feedkeys API function

- New API function to push data to the typeahead buffer - this should
  equivalent to the vimscript feedkeys() function
- In Vim there was a --remote-send command to insert input into a
  Vim server instance. Besides accepting key sequences it also
  translated special keys such as <CR> or <Leader>, backslash notation
  is ignored. This commit backports the original Vim handler for
  --remote-send as a bool option for vim_feedkeys()
- vim-patch:0
dispatch function generator: Fix bug in validation/initialization

- Initialize variables before validating argument count to remove possibility of
  freeing uninitialized pointers
- Set the error when the argument count validation fails
Merge pull request #916 'Add `feedkeys` API function'
Removed unnecessary PATHS from cmake modules

- DEPS_INSTALL_DIR is already set into CMAKE_PREFIX_PATH in
  the main CMakeLists.txt
Merge #910 'Remove unnecessary PATHS from cmake modules'
Move po generation from Make to CMake.

Fixes #902: localization build: `install`, `uninstall`, `prefixcheck
targets.  All the language-related bits will now build under CMake.
Changes include:

  * Moving all non-generated sources into the NEOVIM_SOURCES variable
    to aid in generating the .pot file.
  * Moving a couple generated sources from NEOVIM_SOURCES and into
    NEOVIM_GENERATED_SOURCES.
  * Added NEOVIM_HEADERS to the executable and the library for folks who
    are using something other than Ninja or makefiles (that way the
    headers will show up in the IDE files).
  * Now uses gettext's `--update` switch to update the .po files, rather
    than doing a fragile `mv` dance that could leave you with a broken
    working tree if you press CTRL-C at the right time.
  * Creates `update-${LANG}` targets for updating individual languages,
    just like the original Makefile.
  * Also adds the `update-po` target for updating all the languages.
  * Ported the `check-${LANG}` style targets.
  * Handles all the one-off instances that were in the original
    Makefile.  Fixed up ko.UTF-8.po to include the "Original
    translation" line like other .po files to make the generation of the
    "Generate from ..." comments consistent.  Updated ko.po with the new
    text.
Customize the log file for the check targets based on the input file.

The idea being that it's better to segregate feedback, just in case
someone is working on several translations.  Now the check log will
appear in `./build/src/nvim/po/check-${LANG}.log`.