Emacs 23: don't require skewer or coffee-mode, which now depend on Emacs 24

See #160
Drop git-gutter-fringe, which I never use
Remove duplicated requirement of haml-mode
Make ag ignore archive-contents in this repo
Ignore /history
Use fullframe to run list-packages in a full-frame window
Adjust for updated fullframe API
Don't reindent so eagerly in haml-mode
Expand "-foo" to "modname-foo" in elisp with hippie-expand
string-prefix-p is better than regexp check
Do magic "-foo" to "modname-foo" expansion only after other expansions fail

Otherwise users of dash might get undesirable results.
Handle case where there's no `(provide ...)` form
c