PLYImporter: - optimize memory and speed on ply importer / change parser to use a...

PLYImporter: - optimize memory and speed on ply importer / change parser to use a file stream - manage texture path in ply import - manage texture coords on faces in ply import - correction on point cloud faces generation

IFC :
 - update poly2tri to avoid crash on some IFC files

Collada :
 - manage missing texture reference in collada import