Added unparsed FBX properties to the aiNode's metadata. This allows the
user to extract extra/custom/user attributes/properties from the scene
graph. E.g., extracting attributes set under "extra attributes" in Maya.
Fixed a compile error due to a >> expression in a nested template statement.
Merge pull request #231 from frederikaalund/master

Added unparsed FBX properties to the aiNode's metadata.