patch 8.0.1309: cannot use 'balloonexpr' in a terminal commit https://github.com/vim/vim/commit/51b0f3701ecb440aa72ab6017c1df6940c0e0f6f Author: Bram Moolenaar <Bram@vim.org> Date: Sat Nov 18 18:52:04 2017 +0100 patch 8.0.1309: cannot use 'balloonexpr' in a terminal Problem: Cannot use 'balloonexpr' in a terminal. Solution: Add 'balloonevalterm' and add code to handle mouse movements in a terminal. Initial implementation for Unix with GUI.

This is a MODIFIED version of libvterm.

The original can be found:
- on the original site (tar archive and Bazaar repository):
	http://www.leonerd.org.uk/code/libvterm/
- cloned on Github:
	https://github.com/neovim/libvterm

Modifications:
- Add a .gitignore file.
- Convert from C99 to C90.
- Other changes to support embedding in Vim.