still chuggin along refactoring.  About to undertake something big:  validations are coming out of tag_collection and into tag_info#valid?
refactored validations into seperate function.
refactoring away, stumbled upon an inapropriate assertion.
renamed a method that was misnamed the opposite what it should have been.
hole in test suite found, test_illegal_link.
refactored yet another validation.
Made it so you need to invoke the scan routine manually on the TagCollection object, just to make things more explicit.