Testing improvements from Yngve
- Using junit-5
- using the openxal-lattice image for testing
- adding tests for the quad code (as a demonstration mostly)
- getting rid of the remaining bugs reported by sq. Well, the naked notify I still ignore, we seem to do this a lot in oxal, I see similar bugs in several apps. @juanfestebanmuller please check this part if it looks right to you before accepting the merge. That would be the last three commits.