Create text objects for pairs of characters

Add text text objects for pairs of certain punctuation characters.
Should be useful for objects that are delimited by a character (like
|types| and *tags* in vimhelp). Since surround doesn't support most
symmetrical symbols, this may be useful.

These text objects only operate on a single line.

From Paradigm:
	https://github.com/paradigm/dotfiles/blob/master/.vimrc#L304-L310
Fix vimscript completion to compl-vim

It's not just cmdwin, but all vimscript that has better completion as
<C-x><C-v>. See :help compl-vim

Us it for my completion map in all vimscript.