Efficiency of unit conversion

[mkolopanis]

We might want to move this to the << operator, it can save some time and memory. to make a copy of the entire array. see astropy docs

Definitely a needs investigation and profiling kind of thing.

pyradiosky/pyradiosky/skymodel.py

Lines 806 to 810 in d990f80

	if self.stokes.unit.is_equivalent("Jy"):
	# need the `to(units.Jy)` call because otherwise even though it's in Jy,
	# the units are a CompositeUnit object which doesn't have all the same
	# functionality as a Unit object
	self.stokes = self.stokes.to(units.Jy)