SVGHMI: Fixes UI lifecycle problems

Was sometime showing HMI tree of previously closed project : no more module globals to store hmi tree.
C++ dead object exceptions happened when re-opening SVGHMI UI or building after close of UI.

                  <xsd:element name="Generic">
                    <xsd:complexType>
                      %(toolchain_makefile)s
                    </xsd:complexType>
                  </xsd:element>