Refactoring: Replaced MagData with VectorData and added ScalarData class (and common superclass FieldData).
magnitude is now called field (which is more appropriate)
projector now uses FieldData to process both vector and scalar data (foundation was in place before)

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.

tests: implemented the missing TestCases!
dataset: mask is now created if not given!
phasemapper: guaranteed np.float32 format for RDRC (expected by Cython)
projector: now uses fft.FLOAT

docstrings: updated!
costfunction: CFAdapterScipyCG obsolete, deleted estimate_lambda()
dataset: use_fftw and threads obsolete
diagnostics: implemented stuff... much stuff...
fft: Docstrings and implementation of threads
magcreator: fixed bug in slab (dimension mix-up)
phasemap: plot now also returns colorbar
reconstruction: PrintIterator and optimize_simple_leastsq obsolete
regularisator: Docstrings
scripts: minor modifications
scripts - reconstruct_random_pixels: now use optimize_linear
testcases: analytic, compliance, kernel, magcreator, magdata, projector