File implements some generalized quaternion to/fro Euler angle routines. These are reversible and with +1,1,2,3 (right handed XYZ) template arguments are consistent with the matrix classes. What Euler angle routines are currently defined are not consistent with aiMatrixNxN and may not be accurate.
These routines are not perfect as is. The first ignores the handedness argument (wasn't confident what to do) and the second has some commented out code in the singularity branches which seemed out of place to me. I've adapted the code from different sources online more or less.
At any rate it's a start. Along side the shortcomings mentioned some matrix routines would also be a welcomed addition.
Feel free to change anything you like.as long as the basic functionality is preserved.
In my project space, I've put this file in the include/Cpp folder.