Added Gitter badge
Add "Changelog" section to the documentation.
Merge pull request #801 from StackStorm/STORM-716/st2-version

Move st2client setup from pbr to setuptools
Merge pull request #796 from gitter-badger/gitter-badge

Add a Gitter chat badge to README.md
Merge pull request #803 from StackStorm/add_changelog_to_docs

Add "Changelog" section to the documentation
Add README.md as description to st2client package
Fix st2client deb package

The st2client deb package was created but did not install correctly on ubuntu resulting in error pkg_resources.DistributionNotFound error when executing /usr/bin/st2. This update to st2client Makefile uses stdeb with the bdist_deb option to create the deb package.