Ticket #5823: Properly count template parameters in TemplateSimplifier::useDefaultArgumentValues

Hi,

This patch fixes the ticket by ensuring we properly count arguments in useDefaultArgumentValues when default values are templates with more than one argument.

Somehow this "broke" TestTokenize::cpp0xtemplate3, a TODO_ASSERT. Since it did not bring the expected value, I've had to modify a bit TemplateSimplifier::templateParameters that did not properly handle default values involving casts; it does now and the TODO_ASSERT remains as it was before. The change makes sense IMHO.

Please consider merging.

Cheers,
  Simon