Show the byfname toggle in status line
Remove 'diff' from s:filetype_overrides

I would like to see the normal statusline (i.e. file name) with
diff/patch files, too.
Merge pull request #666 from blueyed/no-ft-override-for-diff

Remove 'diff' from s:filetype_overrides
Merge pull request #651 from chenaren/byfname

Show the byfname toggle in status line of CtrlP