New rotation matrix

Update to sdb2arc() which allows proper facing arcs even if you are at 0 range from eachother.
TODO: Can probably rework this to not use acos() calls, saving some cpu cycles.

Update to sdb2shield() which shows proper facing shield even if you are at 0 range.
Fixed to work with new rotation matrix, saves cpu cycles by trading 3 acos() calls to 3 fabs() calls.