Remove forgotten debug print.
CLI: Adding loading of a polygon mask from an external file.
DB-model: Adding 'semantic' filed to the 'VectorMask' model.
DB-model: Adding related to the 'VectorMask' coverage foreign key.
Automatic setting of the VectorMask semantic.
Changing the default displayed mask type.
WMS: Changing  layer factories to use the DB stored vector masks.