Improved template template parameters support.

Previously, specifying more than one simple template template parameter
resulted in a parse error. Now multiple template template parameters are
working including instantiation with %template. Example:

  template <template<template<class> class, class> class Op, template<class> class X, class Y>
    class C { ... };

Closes #624
Closes #1021

Examples/test-suite/common.mk

@@ -497,6 +497,7 @@ CPP_TEST_CASES += \
 	template_static \
 	template_tbase_template \
 	template_template_parameters \
+	template_template_template_parameters \
 	template_typedef \
 	template_typedef_class_template \
 	template_typedef_cplx \