Re-worked FSC computation and improved symmetry detection

This is the new version 0.7.6.3 (FEB 2022).

The main new features include:

1. The stripe on sphere mapped rotation function for angle 180deg around the equator is now gone.
   a) The cause was an error in rotation matrix to euler angles conversion in the singularity case.
   b) The Euler angles are in ZYZ and NOT in ZXZ format. All references changed.
2. Completely re-worked FSC computation - now it is faster and much more accurate. More specifically:
   a) Binning is improved.
   b) Resolution cut-off for faster computation.
   c) Map rotation now done in reciprocal space (i.e. faster).
3. Improved the symmetry detection logic
   a) There was a wrong axis in the pre-computed optimal Icosahedron, now resolved.
   b) D symmetries are now not simply taken as the highest fold and passing threshold, now smoothened histogram approach is used.
   c) C symmetries and D symmetries are both considered, instead of just taking any D over any C.
4. Speed improvements
   a) If mask is supplied, the inner settings (bandwidth) use the non-zero mask size instead of full map size.
   b) Radius in which the structure is considered and outside of which it is ignored can now be supplied for faster calculations
   c) Improved the peak detection threshold detection, which was causing some structures to take be 10 times slower for symmetry detection.
5. Minor bug fixes and code clean-ups.