Fix failing PLC build when building freshly created project that use default libraries blocks. When controller loads libraries according to attibutes in project files (BeremizRoot/Enable_{libname}_Library), use known default if attribute is missing.
<?xml version='1.0' encoding='utf-8'?>
<BeremizRoot xmlns:xsd="http://www.w3.org/2001/XMLSchema">
<TargetType>
<Generic Command="make -C %(buildpath)s -f ../project_files/Makefile all BEREMIZSRC=%(src)s BEREMIZCFLAGS=%(cflags)s MD5=%(md5)s USE_BEREMIZ=1 FROM_BEREMIZ=1"/>
</TargetType>
<Libraries Enable_Native_Library="false" Enable_Python_Library="false" Enable_SVGUI_Library="false"/>
</BeremizRoot>