Launcher: ShowUI call moves from preStart to start. ShowUI() split into CreateUI() and ShowUI(). Start()'s arguments are passed to CreateUI()
This is meant to allow customizations to pass own pre-instanciated controller to UI at startup.

          <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"/>