- Consider that multiple versions of a feature could be present and
select always the latest one.
- Consider version match rules for required/imported plug-ins of a
feature
- Add unqualified version match as secondary criteria for included
plug-ins

Change-Id: I990c0047400b14d4fd98db5cacaf3968ffb17cce
Signed-off-by: Hannes Wellmann <wellmann.hannes1@gmx.net>
Reviewed-on: https://git.eclipse.org/r/c/pde/eclipse.pde.ui/+/186945
Tested-by: PDE Bot <pde-bot@eclipse.org>