Templates as template arguments

This is a fairly straightforward extension that allows template names to be passed as arguments into templates. This allows, for example, the implementation mechanism for a smart container to be specified as a template argument, e.g.,

	template<class T> class List;
	template<class T> class Vector;
	template<class T, template<class U> class C = List>
	class Group
	{
		// ...
		C<T>	container;
	};
	Group<int>		group_int_list;
	Group<int, Vector>	group_int_vector;

Here, Group is implemented using another container class (a template) which can be specified for each Group instance. The alternative was to specify List<int> or Vector<int> as a type argument but this has two main disadvantages:

• the contained type int is specified twice and errors caused by the type differing in those two places might not be caught
  
• the container cannot choose to create instances of the passed type with different arguments, e.g., Group might want to declare C<T*> for each C<T>