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.
Allow assoc to take many key val pairs
Rename persistent-set-helper to apersistent-set
Merge pull request #20 from patrickgombert/aset

Rename persistent-set-helper to apersistent-set
Merge pull request #19 from patrickgombert/assoc

Allow assoc to take many key val pairs
refactors array-map tests so that they can be reused for other maps
removes order specific and seq tests out of the common map tests
Merge pull request #21 from mylesmegyesi/refactor-map-tests

Refactors array-map tests so that they can be reused for other maps
Allows dissoc to take 0, 1 or more keys
Merge pull request #22 from patrickgombert/dissoc-keys

Allows dissoc to take 0, 1 or more keys
Clarify goals of the project
Implement dissoc and seq for PersistentSortedMap
Pull out APersistentMap. Implement hash and equivalence methods for PersistentSortedMap.
Merge pull request #23 from patrickgombert/sorted-map-dissoc

Sorted map dissoc