Log Message:
Update to 3.1.0

Upstream changes:
3.1.0 2013-11-16 16:46:35+0900
    [BUG FIXES]
    - Close #95; $/ affected the parse() method

    [FEATURES]
    - Add $xslate->validate($file) method to check template syntax

3.0.2 2013-11-15 21:56:53+0900
    [BUG FIXES]
    - Fix a mojibake issue where utf8::upgrade() was always called when
      loading caches (hanabukuro++)

3.0.1 2013-11-04 12:27:51+0900
    [TEST FIXES]
    - Fix a test that might fail on a slow machine like Raspberry Pi
      (Getty++)

3.0.0 2013-10-18 08:59:22+0900
    - No code changes from 2.1.0, just re-packaging for package managers

2.1.0 2013-10-17 22:18:21+0900
    [BUG FIXES]
    - Fix an issue that multi-bytes string literals used for a hash key
      was not dealt as a text string (@Niratama++)
      WARNING: this change could break your code if you use multi-byte
               text string as a hash key.

2.0010 2013-10-07 21:56:12+0900
    [BUG FIXES]
    - Fix an issue that vpath with text-strings raised errors
      on newer perls due to specification changes in PerlIO::scalar (#90)
    - Documentation tweaks (#84, #86)