Support type-template function modifications

Modify typesystem parser to (partly) set the correct context for
function additions/modifications to type-template. Modify
AbstractMetaBuilder::createInstantiationMetaClass to add functions from
the type template to the instantiation.

This is only partly complete; template argument types are not yet
supported as types in the function.

Change-Id: Ie6369d2facf3bcd642e9a2a51cbb107046e9094d