Test script for lenslet array

Computes the intensity distribution in the image plane of a lenslet
array, used to simulate the Shack-Hartmann wavefront sensor. Script runs
stand-alone.
Made small adjustments following from the comments on the test script, added parameters needed for the sensor in main.py and build the mainWFS.py which was mostly already finished in the test script.
Merge branch 'WFSLensletArray'

Conflicts:
	src/WFS/mainWFS.py
	src/main.py

Solved conflicts created by the overlapping code of this branch with the of the just merged single lens system.