Start finding more bugs in Linker::link() by having the Parser use it, and running...

Start finding more bugs in Linker::link() by having the Parser use it, and running the parser tests.
* Support class="extiw"
* Do not double the fragment for external links with fragments.  Move the code for this into a new Title::getLinkUrl() instead of a Linker method, because it seems like a useful concept to be able to get a *usable* link to the current Title.
* Fix a few parser tests that expected attributes in the opposite order.
* Don't overwrite actions for broken links.
* Style

If you want me to stop doing this, by the way, please say so before I spend too many more hours of my life on it.