SVGHMI: better handling of page switch fade-out.
- In cases or relative jump to current page, page was keeping black after switch.
- Now keep track of undergoing page switch without comparing subscribed page to visible page.
<xsd:element name="Xenomai">
<xsd:complexType>
%(toolchain_gcc)s
<xsd:attribute name="XenoConfig" type="xsd:string" use="optional" default="xeno-config"/>
</xsd:complexType>
</xsd:element>