Add in MANIFEST.in to ensure requirements are passed to dist
Add `publish.sh` to allow Jenkins to grok for semver changes

- gets last sha in which a change was made to `performanceplatform/collector/__init__.py` (which contains the package information, including version number)
- extracts the version in __init__.py from that particular moment
- Checks whether that tag exists in github, and if not, publishes with the new version and a generic message
- TODO: better messaging?