Both C- and Python-coded API components were rearranged into logical groups.
New Python modules are packaged as follows:
freestyle - Top-level package
freestyle.types - Classes for core data structues (e.g., view map)
freestyle.chainingiterators - Pre-defined chaining iterators
freestyle.functions - Pre-defined 0D and 1D functions
freestyle.predicates - Pre-defined 0D and 1D predicates
freestyle.shaders - Pre-defined stroke shaders
freestyle.utils - Utility functions
The Python modules are installed in scripts/freestyle/modules. Pre-defined
styles are installed in scripts/freestyle/styles.
To-do: update styles according to the new Freestyle API package structure.
