Added PLCID variable accessible from C side, set with binarie's MD5. Added retain init and cleanup calls. Extended tests/python to test PLCID
<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"/>