[Mvn] Updated build configuration
  - Updated to Tycho-0.18
  - Changed spec of encoding
  - Removed workaround for license-feature

Signed-off-by: Stephan Wahlbrink <sw@wahlbrink.eu>
[Releng] Fixed license url for features

Signed-off-by: Stephan Wahlbrink <sw@wahlbrink.eu>