added trefoil to optical aberration
Merge branch 'master' into #390
Merge branch 'master' into #390
Merge branch 'master' into #390
Merge branch 'master' into #390
Merge branch 'master' into #390
edited to follow the code guidelines (#390)
typos
(#390)
Convention of optical aberration (ordering and normalization) is matched to the Noll convention (#390)
typos (#390)
Merge branch 'master' into #390

Conflicts:
	CHANGELOG.md
added circular_pupil default info
(#390)
Merge branch 'master' into #390
Updated the documentation. Added a unit test. (#390)
Merge branch '#390' of https://github.com/GalSim-developers/GalSim into #390
typo
(#390)
Formatting
(#390)
typo
(#390)
Added a script to generate images for test_optics.py. Added a test which includes all aberrations to the unit test. (#390)
changed all optics comparison images to generate 128x128 aberrations, and recommited updated images
(#390)