Allow multiple policies to be supported

[jsipahio]

The older version of the dispatcher (list-based) allowed for multiple policies to be passed as template arguments. The current version doesn't break when you do this, but only last policy generates notifications. It may be worth looking at supporting multiple policies again.
Example:

// only notifies for functions
srcDispatcher<ClassPolicy, FunctionPolicy> dispatcher(&saxController);
// only notifies for classes
srcDispatcher<FunctionPolicy, ClassPolicy> dispatcher(&saxController);

[mjdecker]

This list-based class was originally the base class. And, the stack-based was the child. These were flopped. This should still work, but the use case if it exists, is limited. Proposal is to consider pushing this down to the child class.