Log Message:
Update ruby-gettext to 2.3.7.

# News

## <a id="2-3-7">2.3.7</a>: 2013-01-11

This is a msgmerge improved release.

### Improvements

  * [msgmerge] Speeded up fuzzy matching.

### Fixes

  * [msgmerge] Fix the bug that msgmerge adds needless fuzzy flag from
    not fuzzy entries in merged PO.
  * [POEntry] Pretty formated all messages except msgstr.

## <a id="2-3-6">2.3.6</a>: 2012-12-19

This is a bug fix release.

### Fixes

  * [POEntry] Fixed the bug that obsolete comment mark (#~) is added
    to already comment.
  * [msgmerge] Fixed the bug that no separator (blank line) didn't exist
    between each obsolete entry.
  * [msgmerge] Fixed tne bug that obsolete entries in old PO file are
    added to new PO file. Any obsolete entries in old PO file aren't
    treated for merging.