Additional functionality for vital Rotation python bindings

[tom-osika]

The bindings for the vital type Rotation were completely redone in dc210e576a5b74d1ebff0a467848f0644072c4b6. One limitation of these new bindings is that some functions can only be called with rotations of the same template type as parameters (float or double). This is the case with the C++ implementation, but may be inconvenient for Python users. These functions are:

1.) interpolated_rotations 2.) interpolate_rotation 3.) __mul__ 4.) __eq__ 5.) __ne__