Function made to ouptut the cleaned PHASES and the new mag based
on removal of bad magnitude. Bad magnitudes are removed if they are outside
n*sigma where n is an input.
Amplitudes and magnitudes are not removed for bad phases they are just set
with a 0 flag (see PHASES.WRITE_FLAG) so that we know that this magnitude will
not be used in the written output (event2nor), write-flag only concerns
amplitudes writing, not picks

Input:
PHASES: input PHASES that has to be cleaned
n: into n*sigma (usually in that cases for magnitude we will take 1 or 2)

Output:
OUT_PHASES: cleaned phases
new_mag: new magnitude computed after removal