1. Added support for loading sub-objects in .OBJ into a generic
attribute.
2. Added missing mesh_are_equivlent classes needed for certain unit
tests.
3. Updated javascript decoder reflecting our latest changes + added
support for GeometryAttribute::custom_id() method.
4. Added checks for valid quantization bits to our draco_encoder app.
1. Fixed crasher when dependent attributes were encoded.
2. Improved documentation to PointCloud::AddAttribute() methods
3. Fixed some of the inconsistencies with int64_t vs size_t usage
4. Fixed potential IO problems when the input stream does not start from 0.
