Allow to overwritte constraints from getScreenConstraints
Allow to overwritte constraints from getScreenConstraints

Change-Id: I0be85b4e272e0fc4f0a66ffc376949878254495e

shelsonjava/kurento-utils-js,shelsonjava/kurento-utils-js,lcamacho/kurento-utils-js,lcamacho/kurento-utils-js