Don't auto-enable electric-indent-mode in 24.3, where it is rubbish

Closes #236
Prefer #'version< to #'string<
Don't override RET in ruby-mode
Enable guide-key for more prefix keys
Merge branch 'master' of github.com:purcell/emacs.d into purcell-master

Conflicts:
	lisp/init-editing-utils.el
	lisp/init-ruby-mode.el
	lisp/init-sessions.el
Merge branch 'purcell-master'