SVGHMI: optimization of C part : stop traversing the whole HMI tree, use dual linked list for subscriptions and single linked list for changes from HMI. Intermediate commit, still crashing in some cases.
<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"/>