Add snap line to more angles (fix #1641)
I'll review the tests that are failing.
I can change MAX_M from 8 to 2 to allow immediate inclusion of this pull request, then I can send a new commit that will add an additional checkbox to enable/disable more perfect slopes in Edit > Preferences > Editor > Line Tool with more snap slopes (disabled by default).
clang-tidy review says "All clean, LGTM! :+1:"
I think we talked about adding an option to enable this. Probably I'm missing something from the PR.
This last change removes the static variable fixed_step_tilt in algo.h and replaces it with explicit parameter passing through std::function callback.
@martincapello suggested this approach, which I wasn’t familiar with. Thank you!