SVGHMI: continue rework of Jump widget to cope with Enable Expressions.

Questioning widget's activity and disability all together.
Now active/inactive/disable masquarade is all managed in widgets_common.
Propagated changes to widget already using activity (buttons)

          <xsd:attribute name="Command" type="xsd:string" use="optional" default="make -C %(buildpath)s all BEREMIZSRC=%(src)s BEREMIZCFLAGS=%(cflags)s MD5=%(md5)s USE_BEREMIZ=1 FROM_BEREMIZ=1"/>