Update to 1.27

Upstream changes:
2016-04-25 v1.27 pjacklam
  * Sync test files with Math-BigInt-1.999719.

2016-04-22 v1.26 pjacklam
  * Sync test files with Math-BigInt-1.999718.

2016-01-03 v1.25 pjacklam
  * Sync test files with Math-BigInt-1.999714.

2015-12-31 v1.24 pjacklam
  * Sync test files with Math-BigInt-1.999713.

2015-11-22 v1.23 pjacklam
  * Sync test files with Math-BigInt-1.999709.
  * In v1.22 the required version of Math-BigInt was set to 1.999703, but it
    should have been 1.999706. The required version is now 1.999709.
  * Correct error in CHANGES file.

2015-11-09 v1.22 pjacklam
  * Sync test files with Math-BigInt-1.999709.
  * Update the README file.
  * Remove the LICENSE file as this information is already covered in the file
    README.
  * Replace 'use vars ...' with 'our ...'. We require a Perl newer than 5.6.0
    anyway.
  * Move 'Test::More' from 'build_requires' to 'test_requires' in Makefile.PL.
  * Enable 'use warnings'. We require a Perl newer than 5.6.0 anyway.
  * Add 'assertlib.*\.exe' to MANIFEST.SKIP, since make generates temporary
    files like 'assertlibzxjE4WfG.exe' on Cygwin.

2015-09-21 v1.21 pjacklam
  * Sync test files with Math-BigInt-1.999703.
  * Required version of Math-BigInt is now 1.999703.
  * Update author information.

2015-09-17 v1.20 pjacklam
  * Sync test files with Math-BigInt-1.999702.
  * Required version of Math-BigInt is now 1.999702.

2015-09-11 v1.19 pjacklam
bigfltpm.inc
  * File removed. It was included in the previous release by accident.
bigfltpm.t
  * File removed. It was included in the previous release by accident.
bigintpm.inc
  * File removed. It was included in the previous release by accident.
bigintpm.t
  * File removed. It was included in the previous release by accident.
biglog.t
  * File removed. It was included in the previous release by accident.
bigroot.t
  * File removed. It was included in the previous release by accident.
inc/Module/Install.pm
  * Update bundled Module::Install from v1.08 to v1.16.
lib/Math/BigInt/Pari.pm
  * Updated version number.
  * Fixed bug in _modpow().
Makefile.PL
  * Updated required version of Math::BigInt to 1.999701.
t/01load.t
  * Improve formatting of module version information.
t/03podcov.t
  * Slight reformatting and better information message.
t/bigfltpm.inc
  * Sync tests with the Math-BigInt distribution.
t/bigfltpm.t
  * Adjust number of tests.
  * Sync tests with the Math-BigInt distribution.
  * Make sure we test Math::BigInt::Pari, not Math::BigInt::Calc.
t/bigintpm.inc
  * Sync tests with the Math-BigInt distribution.
t/bigintpm.t
  * Adjust number of tests.
  * Make sure we test Math::BigInt::Pari, not Math::BigInt::Calc.
t/biglog.t
  * Adjust number of tests.
  * Sync tests with the Math-BigInt distribution.
  * Make sure we test Math::BigInt::Pari, not Math::BigInt::Calc.
t/bigroot.t
  * Adjust number of tests.
  * Make sure we test Math::BigInt::Pari, not Math::BigInt::Calc.
t/*.t
  * Add "use warnings" to test scripts, since Perl 5.6.2 is required anyway,
    and "use warnings" was introduced in Perl 5.6.1.
  * Modified test scripts so the difference between the test files in the
    Math-BigInt distribution and the backend distributions are as few and as
    small as possible. This makes for easier release management.

2014-04-03 v1.18 pjacklam
* Updated test files from the Math::BigInt distribution (Peter John Acklam).
* Updated POD (Peter John Acklam)

2011-09-04 v1.17 pjacklam
* Upgrade bundled modules in "inc" to latest version. (Peter John Acklam)
* Math::BigInt::GMP now requires Math::BigInt v1.997 (Peter John Acklam).
* Include "^MYMETA\.(yml|json)\z" in MANIFEST.SKIP. Whereas META.* are
  generated by the distribution author at packaging time, MYMETA.* are
  generated by the end user at configure time after any dynamic
  dependencies are known. (Peter John Acklam)
* Updated common test files from the Math::BigInt distribution. (Peter
  John Acklam)

(wen)