Fixed bug: need conjugate transpose = .T.conj().
Bugfix: required zern library for zernactmat
Doc re-order + update
Add option to make plots non-interactively
Add sim_shwfs(), fix typo

sim_shwfs: simulate SHWFS given a complex input wave
calc_cog: rename check keyword to clipcheck for clarity
Add getcomplex opt. for avg_phase(), extend doc
Improved code, 2x faster
Added option for fixed #modes for influence calib

Besides amount of singval to use, also allow specification
of number of modes to use (positive) or discard (negative)
Allow re-use of Zernike cache