Allow GLMeshItem to draw edges from MeshData with face-indexed vertexes.
All scipy imports in the library are now optional (need to test each of these changes)
Several examples still require scipy.
corrected import
colormap no longer requires scipy.interpolate
Added SRTTransform3D test, corrected fromMatrix bug
added test for solve3DTransform
PlotDataItem._fourierTransform now uses np.interp
Added pure-python implementation of scipy.ndimage.map_coordinates
Expanded capabilities of interpolateArray function to support broadcasting
Added pg.gaussianFilter, removed all dependency on gaussian_filter
Removed all dependencies on scipy.

Merge branch 'make_scipy_optional' into develop
Update README to reflect loss of scipy dependency
Fixed multiprocess port re-use on windows
Corrected bug in multiprocess causing deadlock at exit
Multiprocess debugging messages now use one color per process
Corrected RemoteGraphicsView not setting correct pg options on remote
process

New debugging tools:
* util.cprint for printing color on terminal (based on colorama)
* debug.ThreadColor causes each thread to print in a different color
* debug.PeriodicTrace used for debugging deadlocks
* Mutex for detecting deadlocks
clean up debug messages
Rename Mutex module
Fixed multiprocess deadlock on windows
Added several utilities and debugging tools
Merge branch 'multiprocess-fix' into develop
Removed extra image window from VideoSpeedTest
Fixed GLGridItem.setSize, added setSpacing
BarGraphItem: add setPen and setBrush methods