Fix dom stripping

*do not merge. Under construction*.

This is here to get some feedback from @crawljax/owners.

The Oracle comparators are now gone because

1. They do not adhere to the plug-in architecture.
2. They are not configurable enough
3. They were not used consistently throughout the application
4. They weren't thread safe

The new DOM strippers offer much more flexibility. Here's how they'll work:
The idea is that you define zero or more of these strippers. They do not have to produce a valid DOM, but they're there so you can influence how DOMs are compared. StateVertexes are compared on the equals function of these stripped doms so the more alike you make them, the less states you'll have at the end of your crawl.