C4DImporter: support for reading texture paths.
C4DImporter: support reading normal and UVW mesh channels.
C4DImporter: bugfix material loading.
C4DImporter: better logging.
C4DImporter: fix node names.
C4DImporter: flip y axis of UV coordinates.
C4DImporter: avoid generating multiple default materials.
Merge branch 'master' of github.com:acgessler/assimp-cinema4d