Merge branch 'master' into #442

Conflicts:
	galsim/optics.py
Clarify comment in Lanczos xCalc
(#442)
Some speed ups to Lanczos using trig identities to avoid multiple sin calls.
(#442)
add tests for n=4,6,8 to Lanczos conserve flux tests
(#442)
Simplify logic slightly in simReal
(#442)
Remove comment where I started trying to improve the uCalc calculation and aborted.
(#442)
Merge branch '#442' into #449