Add dtype option to draw commands
(#526)
Use dtype=float64 in addnoisesnr test, and up the required accuracy to 8 digits
(#526)
Slight edit to addNoiseSNR to pull out a calculation common to both branches.
(#526)
Add properties for the things that are currently getters in Noise classes
(#526)
Expand on the discouraged comment in the docs for setters in Noise classes
(#526)
Merge branch '#526' of github.com:GalSim-developers/GalSim into #526

Conflicts:
	tests/test_random.py