Convert internally-stored networks in the collection module to new 'gt' format
Change default colormap in draw module
Include documentation for the 'gt' format
Default intersphinx version to python 3
Stylistic changes to the documentation
Change default colormap
Change default colors in draw.cairo_draw
Modify automatic text color selection heuristic
Refactor SBM code and implement overlapping model
Small performance improvement to sfdp_layout()
Modify docstring tests after RNG update