Upgraded BND and BNDTOOLS to 2.3 and added Gradle support with toplevel build.gradle
Resolved bnd buildpath and external libraries to not rely on Eclipse build path

Resolves #17, resolves #32
Removed all build.xml files of old ant for bndtools.

Resolves #17, resolves #32
Merge pull request #47 from flexiblepower/development_hans

Upgraded bnd to 2.3 and added gradle support