Update to 2.00

Upstream changes:
2.00 2014-06-30T11:15:05Z
    - Deprecation of Readonly::XS as a requirement for fast, readonly
      scalars is complete. Report any lingering issues on the tracker
      ASAP.

1.61 2014-06-28T11:22:13Z
    - Normal constants (strings, numbers) do not appear to be read only to
      Internals::SvREADONLY($) but perl itself doesn't miss a beat when you
      attempt to assign a value to them. Fixing test regression in
      t/general/reassign.t

1.60 2014-06-27T15:59:27Z
    - Fix array and hash tie() while in XS mode (exposed by Params::Validate tests)
    - Fix implicit undef value regression resolves #8
    - Minor documentation fixes (spell check, etc.)
    - Patch from Gregor Herrmann <gregoa@debian.org> resolves #7

v1.500.0 2014-06-25T19:56:18Z
    - PLEASE NOTE: Readonly::XS is no longer needed!
    - Again, Readonly::XS is no longer needed.
    - Merged typo fix from David Steinbrunner RT#86350/#2
    - Merged patch (w/ tests, yay!) from Daniel P. Risse RT#37864
    - Upstream magic related bugs were reported to p5p and fixed in perl
      itself so we can resolve the following local issues: RT#70167, RT#57382,
      RT#29487, RT#36653, RT#24216.
    - Reported RT#120122 (tie + smartmatch bug) upstream to p5p. Will
      eventually resolve local [RT#59256].
    - Note: Resolved RT#16167 (benchmark.pl being installed) in 1.04.
    - Use readonly support exposed in Internals on perl >=5.8.x
    - Have I mentioned you don't need to install Readonly::XS anymore?
    - Checking $Readonly::XSokay is no longer suggested. ...never should have been

(wen)