Add sh template, snippets; add template filetypes.

Add:
	vim/(ultisnips/sh.snippets, templates/sh.tmp)
		-Add `bash` snippets and a template file identical to that of
		`zsh`.

	vimrc
		-Add filetype detection for template files (for the language
		that they're being written for).

	zshrc
		-Add some miscellaneous aliases.

Mod:
	vim/templates/zsh.tmp
		-Add a file-header documentation comment.