In GUI, remove option to switch beteen nm and angstrom, degrees and radians.
There used to be a button that allowed users to switch displayed units beteen nm and angstrom and degrees and radians. I cannot find that button any longer. Anyway, I rather propose to remove the entire unit switching functionality for good. Rationale:
- It bloats the code.
- It is partly broken (label updating leads to multiple display of units #755 (closed); code for radian unused?).
- It will continue to seed confusion. Better force all users to work with the same set of units.