Many Doctring corrections, all plots now have a "show" parameter to not show a
plot at the end of the method (needed for guis and such).
magdata: quiver_plot: axis switch for x-projection, implemented logarithmic
         arrows and scaling feature.
projector: added to_mag_data() method to directly produce a projected
           magnetization distribution.
gui/create_logo: removed (obsolete and unuseful).
gui/mag_slicer: added!