Updated build to support new scala bundles

* Cleaned-up the build as it does no longer need to depend on a scala-ide p2
repo to retrieve the scala bundles (Tycho now uses plain maven dependencies).

* Dropped support for Scala 2.9 as it is incompatible with 2.10+. And added
profile for compiling against Scala 2.11.

* Updated version of both Tycho and scala-maven plugin.