testing improvements; add test for InverseTransmission
Relocates InverseTransmission function; fixes issue #8

Using a relative import in SAMC class enables putting this function back
in optics.py again.
All unit tests pass.
docs update
catching up with upstream, v.0.3.3.dev
merge with latest upstream version
added resampling of the optic in getPhasor, using scipy.ndimage.interpolation.zoom