Created BndWorkspaceRepository, which hooks into the "BND" workspace.

This allows you to reference projects in your bnd workspace that
might not be in your eclipse workspace OR might be closed in your
eclipse workspace.

Adjusted NewProjectResourceListener to turn project references into
.jar file references when a project is closed or removed from eclipse.
Likewise a .jar file reference is turned back into a project reference
if a project is opened in eclipse too.

All of this is useful if you have a subset of your total number of
projects where changes are occurring. You can minimize what all
gets rebuilt as you make changes.



I know this isn't as "pluginable" as one would like, however, I ran into problems attempting to put this into the bndtools.plugins project. If this is really where it should go, there were several bndtools.core packages that weren't exported to allow it.

Comments welcome :)