Fix #687: OS version must not be parsed with an OSGi-version parser

Signed-off-by: Ferry Huberts <ferry.huberts@pelagic.nl>
Processor: use some predefined strings in the native_capability macro

Signed-off-by: Ferry Huberts <ferry.huberts@pelagic.nl>
Processor: allow overrides to be specified in the native_capability

Signed-off-by: Ferry Huberts <ferry.huberts@pelagic.nl>
Added method to RepositoryListenerPlugin