Merge from origin/emacs-24

The following commits were skipped:

17ad6f8 Fix problems caused by calling 'recenter' in auto-revert  (Bug#20122)
1c4900d Backport: ruby-mode: Detect regexps after `!'
f74843a Backport: ruby-mode: Change faces used for self, true, false and nil
a5d1f94 Backport: ruby-mode: Expect regexp after { or | too