beremiz

Copy description when DnD variables from Globals in resources and configuration variable panels to POUs. Also prevent making exception in case some other DropSource wouldn't provide description.
<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"/>