issue #4496: dumb commit, just trigger a new build on Travis CI.

Issue #4496: use a better way to compare ndarrays in unit-test.

Issue #4496: changes according to code review. Bug description moved to doc/source/release.rst, unit-test rewritten to check calculated data against test vector.

Fix issue #4496: tslib.tz_convert(vals, tz1, tz2) may raise an IndexError exception.