Matrix to euler angles is not stable around sphere poles

[MohamadHarastani]

FYI:
This matrix https://github.com/scipion-em/scipion-em-continuousflex/blob/master/continuousflex/protocols/utilities/dynamo.py#L40 is not stable. It is used multiple times in continuousflex. It is correct in most of the situations but not around the poles (zero angles and opposite to it).

The usage of this matrix should be replaced by
from pwem.convert.transformations import (translation_from_matrix, euler_from_matrix)

A usage example is here
https://github.com/I2PC/scipion-em-xmipp/blob/devel/xmipp3/convert/convert.py#L1339

Whenever you are working on convert a transformation matrix to euler angles try to use the new function

Mohamad