homogenizing levels in cdmodel tests
(#524)
Merge branch '#524' of ssh://github.com/GalSim-developers/GalSim into #524
updates to cdmodel:
* using 2d instead of flattened arrays for shift coefficient matrices
* moved checks of array dimensions from c++ to python layer
* fixing level comparisons in test_cdmodel
(#524)
Merge branch '#524' of ssh://github.com/GalSim-developers/GalSim into #524