beremiz

modbus plugin: add (user accessible) transaction bool flags for servers/slaves; FIX BUG in previous commit affecting RTU slaves.
<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"/>