inline.py

Making various c++ functions and their calls more in line with the HDK by
converting attribute/group types to the corresponding enum type values in
GA_Types.h so they can be directly cast to the appropriate type enum.

createPoints now internally used Houdini 12.5's new appendPointBlock.

Code cleanup.

Additional module documention and function ordering.

test_inline.py

Added tests for variable manipulation and sorting by attributes.

Implemented test for checking shared edges between faces.

Updated test for destroying empty groups since the type specific functions
no longer exist.