(#33) - jshint the tests
(#23) - use binarySearch for options.start too
(#25) - update abstract-leveldown, fix Uint8Array error
(#7) - get tests passing in testling
(#27) - test against full abstract-leveldown suite

Also fix the iterator logic for new API additions
like gt, gte, lt, lte, and exclusiveStart. Much of
the code is copied wholesale from MemDOWN, since they
did it correctly over there.