Enable controls as per permissions
Remove obsolete test
Object to hold read only data.  On file load, if the file is non empty,
the model root is empty.  The data in the file is parsed and loaded into
the model root.  But if the shared permissions are read only, the data
cannot be loaded onto the model root.  So using a local data structure.
All read calls to the positions, elements, relations, nuggets are routed
to this local object.
Disable context menu for read only makings
Merge branch 'permissions'