Create potion-mode.el

A simple generic-mode based mode for edition Potion code, with
syntax highlighting and handling of ":" and "." as matching brackets.
Added LANG directive per Gerd Pokorra
Don't think _why's answering email.
Merge pull request #22 from seano-cpan/master

Add potion-mode.el for Emacs -- Thanks!
Merge remote-tracking branch 'upstream/master'

Fixed conflicts:
	Makefile
(removed silent contact address)