Fix PA error calculation in gaul2srl.py

[AlexKurek]

The std must be computed in circular space in this case.

[gmloose]

This is probably a good improvement, but I would like @darafferty's view on this as well.

[AlexKurek]

Actually there also are:
https://docs.astropy.org/en/latest/api/astropy.stats.circstats.circstd.html#astropy.stats.circstats.circstd
and
https://docs.scipy.org/doc/scipy/reference/generated/scipy.stats.circstd.html
Probably better to use one of those.

[gmloose]

Actually there also are: https://docs.astropy.org/en/latest/api/astropy.stats.circstats.circstd.html#astropy.stats.circstats.circstd and https://docs.scipy.org/doc/scipy/reference/generated/scipy.stats.circstd.html Probably better to use one of those.

Yeah, I just stumbed over the latter one. So, maybe it's indeed better to use one of those two.

[darafferty]

Ah yes, good find. Agreed it should be done with circular stats.

[AlexKurek]

Done.