Improves ido-recentf-open

Two main improvements over the old version:
* Expands ~ to your home directory
* Doesn't have the bug preventing you from opening your most recent file

Written by Steve Purcell:
http://www.reddit.com/r/emacs/comments/21a4p9/use_recentf_and_ido_together/cgc8f6b
Merge pull request #4 from MatthewDarling/master

Improves ido-recentf-open