Fixed dead references of API identifiers (e.g., freestyle.types.Interface0D)
due to relocations of the identifiers into submodules. Also made various minor
revisions of mark-ups and typos.
Removed the previous changes for passing a line style through the Controller, and
revised the BlenderTextureShader to assign the shader node tree of a line style
(if specified) to strokes. This way the assignment of shading nodes can be done
through both the Freestyle GUI and Python scripting.
