Update to 2.12

Upstream changes:
2.12     2015-10-09
    - RT 105935 Change ERROR HANDLING doc section to be very clear about the
      error handling mechanism for root nodes.
    - RT 105935 Change ERROR HANDLING doc section to remove the EXPERIMENTAL
      note; the error handling mechanism has been in place for several versions.

2.11_004 2015-10-01
    - RT 105935 Revert change made in 2.10_001 to carp on failure to find root
      directory when performing an rmtree.

2.11_003 2015-08-03
    - Fix root tests to properly call prereq() -- failed primarily on Windows
      since getpwent/getgrent not implemented on Windows.

2.11_002 2015-07-25
    - Fix windows refactored tests - missing import and since it's out of
      Path.t the path creation creates 2 directories (t/Path_win32.t)
    - Fix root only tests.  getpwent/getgrent was called twice, causing
      skip_all to trigger and giving impression all tests pass.

2.11_001 2015-07-24
    - RT 105527 FIX: Move eg/ and author tests from t/Path.t to xt/
    - RT 105935 FIX: Clarify error behavior for rmtree errors on root directory
      (not fixed but documented).  Clarify in documentation the how alike
      rmtree is to 'rm -r'.
    - RT 105977 FIX: Fix INSTALLDIRS for Perl 5.6
    - RT 105986 FIX: Refactor unit tests to better care for test counts
    - RT 106039 FIX: Wrong version in Pod
    - RT 106043 FIX: Suboptimal error message
    - RT 106045 FIX: _run_for_warning does not consume multiple messages
    - RT 106047 FIX: _run_for_verbose cause fail test on 5.6.2
    - Removed optional File::Output usage and run those tests for everyone.


(wen)