mtplot: added ability to plot normalized_skew as described by Booker, 2014
added utils/shapefiles.py which will convert phase tensors and induction arrows into shape files for GIS visualization programs like ArcGIS or QGIS, need osgeo to be installed if you want to use it.
added documentation to utils/shapefiles.py
utils/shapefile: added ability to project to different UTM coordinate systems
Fixed utils/shapefiles.py to output correct projection file
Fixed utils/shapefiles.py to output correct projection file
Edi.py - allowing to read longitudes in format [0,360] - converting internally to [-180,180]

Signed-off-by: LK <LK@uni>
fixed plotting residual phase tensors as a pseudo section, there is still something a little different then the old one.
added plotstrike2d, which will plot strike for only those responses which are 2d according to mtpy.analysis.dimensionality
fixed plot residual phase tensor maps and pseudo sections to be similar to paralana data
fixed plotting residual phase tensors
fixed plotting residual phase tensors
documenting usgs.zen
fixed plotresidualptps._compute_residual_pt, it computes correct frequencies now
fixed plotresidualptmaps._compute_residual_pt, it computes correct frequencies now
fixed plotresidualptmaps._compute_residual_pt, it computes correct frequencies now
fixed plotresidualptps
added documentation to mtpy.usgs
fixed plot_residual_pt_maps and ps
added ellipse_scale to plot_residual_pt_maps and ps so the user can control how the ellipses are normalized.