Added metadata to PRT file format, bumping the external version to 1.1 and internal version to 2. Metadata is supported via an 'any' object that can contain literally any data (modelled after Boost.Any). Included several 'standard' metadata atrtibutes like BoundBox, DistanceUnits, CoordSys, etc.
Moved cmake stuff into a separate folder so it wasn't dumping files into the project root folder