Make sure mlagrid is an ndarray
Add calc_phasevec with test to compute phase

Given complex waves, fringe.calc_phasevec() computes the phase
represented in some basis (e.g. Zernikes or system modes), using either
scalar, gradient or vshwfs fitting.
Re-arrange plots to causal order
Implemented cache use for calc_phasevec

Basis mode matrix is now derived to an appropriate form automatically
using caching to speed up things. This way we don't have to do it in our
own code each time and we don't make mistakes.
Add pow_list to return FFT power

FFT power can be useful for diagnostics
Remove mean phase also from fitting
Fix bug in caching mechanism
Added plot of relative singular value sum
Minor code comment fix
Store modes used and total modes
Check if binfac is legal
Fix: forgot to close one plot window used
Fix: test was inverted
If binfac not suitable, return input data
Check if binfac is legal before binning
Make phase calculation weighting optional
Allow binning for side band finding
Check if cpeak != None before < 0
Improve carr. freq calibration

- Use average power spectrum: side bands should be smoother
- Use smothed power spectrum instead of binned: gives better resolution
Only return FFT power if requested