Fix "Commentary:" line
Require 'compile at compile-time to reduce byte-compilation warnings
Declare vars in one shot, use define-derived-mode, fix docstrings
Drop reference to var removed from Emacs in 2004
Remove "interactive" from non-interactive function
Add autoload cookie
Tidy up usage instructions
Fix indentation
Add missing docstring
Merge pull request #1 from purcell/master

Changes from Steve Purcell (who has clearly spent way too much time in Emacs to remember that compilation-file-regexp-alist was removed in Emacs back in 2004 :)