Started work with SBuildResolver as OSGi Service.

The SBuildResolever interface is pure Java and thus can be implemented in multiple binary incompatible Scala versions.

Started to first implementation by reusing most of the existing code.
Updated project setup to create update sites with the new bundles.
Update build documentation.
Explicitly scan and start bundles providing SBuildResolver services.

This is a workaround around some Eclipse limitations, e.g. the bundles, once installed, won't get started and thus can not bring there services to the whiteboard. The workaround scans all bundles once and start those, which have a special manifest entry (SBuild-Service).
Removed commented out code.
Change collection type in Resolver API and some other changes.
Added some API doc.
Create .travis.yml
Improved logging.
Fixed container-refresh after change by back-patching.
Use SBuildResolver interface from external project.
Get the resolver from the activator.
Moved working resolver into separate bundle.
Removed obsolete SBuildResolver.
Switched to Scala 2.11.2 and ScalaTest 2.2.0.
Fixed travis config.
Added resolver for SBuild 0.7.9013 (experimental).
Moved some variable into separate object.
Added deepClean target.
Downgraded minimal SBuild version.