parallel/angled constraint is not implemented at moment. I will add soon. In theory it can be implemented adding one new constraint.
First, I will split it up:
1) Parallel constraint: Very easy as only to align one axis. (I will add it shortly in next versions)
2) Angled constraint: Have to think about implementation of additional rotation axis. (will need a bit more time)
Your test where on RealThunder's branch. Yeah! Perhaps it is possible to use his toponaming. (If he will allow!