feature parity on =, == and hash for numbers
revert to using clojure 1.5.1 because we don't need 1.6 anymor
test against clojure.lang.BigInt again
longBitXor
Merge pull request #17 from mylesmegyesi/nums

Feature parity on equality, equivalence and hashCode for Numbers
Introduce PersistentSortedMap. Implements count, get, contains?, assoc.
Merge pull request #18 from patrickgombert/persistent-sorted-map

Introduce PersistentSortedMap. Implements count, lookup, assoc.