Sorted map dissoc

I want to definitely either 

- find all insert/removal rebalancing cases and write tests for them

or
 
- write generative tests for large sorted-maps that will hit all cases

before considering sorted-map complete.

In the mean time, our current test suite is passing. I was able to abstract hash and equals (equals now works for comparing any type of map to any type of map).

I will do the tests I mentioned after I get over being sick. I can't really stand to look at a monitor for too long right now...