WFS update, and added function for rectangular setups in the main

Increased the readability of mainWFS.py.
Normalized the intensity distribution and the lensletCentx/y.
Added support length for FFT in the parameters for the sensors.
Added function in main to handle rectangular lenslet configurations.
 
Yeah, this is one thing I don't really know what is better.
@JaccovdS: You will be using the data. Does it make sense to have the data decoupled, and get the spatial dimensions by a function? Or does it make more sense to have the data all together coming from the wfs function?