Upgrade to Tycho 2.7.0
Upgrade from 2.5.0 to 2.7.0.
See:
- https://github.com/eclipse/tycho/blob/master/RELEASE_NOTES.md#260
- https://github.com/eclipse/tycho/blob/master/RELEASE_NOTES.md#270
This could potentially also help with #111 (closed) and !256 (closed).