Reads the .dxf file data of this object. 

Returns the filer status.

This function is called by dxfIn() to allow the object to read its data. When overriding this function:

1. Call assertWriteEnabled().
2. Call the parent class's dwgInFields(pFiler).
3. If it returns eOK, continue; otherwise return whatever the parent's dxfInFields(pFiler) returned.
4. Call the OdDbDxfFiler(pFiler) methods to read each of the object's data items in the order they were written.
5. Return pFiler->filerStatus().