Update to 0.13

Upstream changes:
0.13 2016-07-02 NEILB
    - Switched to using Test::RequiresInternet rather than the hand-rolled
      online() function that was duplicated in 2 tests. Plus it was testing
      whether google.com was contactable, and not the site used in the tests.

0.12 2016-06-23 NEILB
    - Travis support added by Jason Hall.
    - Added list of contributors to the doc.

(wen)