kernel: u and v are switched and now finally correct.
        get_elementary_phase is also switched and corrected.
phasemapper: added PhaseMapperCharge from Feng Shan.
forward_model: now uses y instead of phase_vec/Se_inv and now direct properties.
costfunction: corrected some docstrings and documentation comments.
fielddata: corrected some missing integer divisions (// instead of /),
        added plot_streamline().

fieldconverter: methods to convert M to A to B
magdata: a bit more parameters for quiver_plot3d(), added contour_plot3d()
phasemapper: pm() extended for different projections (not just simple)
kernel: u and v switched (now named after the unit magnetization direction, which makes much more sense)

colormap: Added TransparentColormap.
magdata: Added get_magslice method, to_emd and from_emd.
phasemap: Added to_emd and from_emd.
gui: New GUI "PhaseMap Creator".
tests: Moved from ./tests to ./pyramid/tests. Not a package anymore!