Remove git commit template.

gitconfig, git/gitcommit.tmp
	-Remove old git commit message template, because I don't make
	effective use of the "add|rem|ref" etc. specifiers.

vim/ftplugin/gitcommit.vim
	-Revise vim syntax matches to accommodate my new commit message
	format.
Miscellaneous ftplugin changes.

vim/ftplugin/*.vim
	-Miscellaneous additions/removals from various `vim ftplugin`
	files.
Miscellaneous ultisnips additions/removals.

vim/ultisnips/*.snippets
	-Add and remove some `snippet`s to several `ultisnips` files.