Completed the restructuring of the package

scripts: changed scripts to work with the new syntax of the package
PhaseMag and MagData: added load and save options for NetCDF files
MagData: changed 3D-plotting to use mayavi (faster and better looking)
test: added more TestCases for various modules
phasemapper: added computation method to use mx and my (now standard)
compare_method_errors: first draft of script to compare the different errors