Mainly implementation of diagnostics class! ... And stuff!

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