Bump version to 6.1.0

Bump travis to test 6.0.0 GA

Version bump to 5.5.1

Version bump to 5.5.0

skip test_elasticsearch2 in MANIFEST

Version bump for release

version bump for 5.3

bump version to 2.0

bunp version to 5.1.0 for release

version bump to 2.4.1