Fix the parser's behavior for the --no-force-templates switch

[maxdebayser]

There are some cases where a method returns a a template specialization like vector. In these cases clang doesn't include the templates definition in the AST, only its declaration. The reason is that a forward declaration of the type would enough. But because we can't emit meta-data for methods that depend on incomplete types, we force clang to instatiate the template. There is a switch that disables this behavior but it is broken since I've made the parser build its own representation of the translation unit instead of printing the meta-data directly.