Cleanup and documentation!
ramp: New class for polynomial ramps. Instantiated in the ForwardModel.
forwardmodel: Now uses new ramp class.
phasemapper: Ramp functionality moved to ramp class.
reconstruction: Ramp order not used, ramp can be now retrieved from the ramp
                class after reconstruction.
analytic, magcreator: Better and consistent definition of pixel centers and
                      their influence on the phase.
testing: Minor corrections for new syntax.

Phase maps now also have a mask and a confidence matrix.
Began new script structure (temporary folders created).
Cleanup, logging and documentation done.
config: NTHREADS is now set here.
dataset: Method for creating 3D masks added.
phasemap: Mask and confidence matrix added. Padding and cropping supported.
forwardmodel: Stubs for multiprocessing added (next TODO!).
kernel: Added support for perturbed reference wave.
magdata: Padding and cropping supported.
projector: New property 'sparsity' introduced.
regularisator: Stub for ComboRegularisator added (next TODO!).
tests: Changed accordingly.

projector: RotTiltProjector implemented!
quaternion: New module providing quaternions!