adds list creation and count
adds meta and empty to list
adds pop peek empty to list
use defseq for persistent list
adds EmptyList
return nil for -first with nil
Merge pull request #61 from kevinbuch/persistent-list

Persistent list
Add unsigned bit shift right

  Bump to clojure 1.6.0 since unsigned-bit-shift-right was added in
  1.6.0
Merge pull request #62 from patrickgombert/unsigned-bit-shift-right

Add unsigned bit shift right
Implement number equality
Move bit-count into platform/hash_map
Implement zero?
Implement vary-meta
Pull out meta-functions specific test
Merge pull request #65 from patrickgombert/meta

Meta
Merge pull request #63 from patrickgombert/number-equals

Implement number equality
Remove vary-meta test from persistent-map-test

  Vary-meta is composed of functions from the meta interface. This
  composition is already tested by meta-test.
Implement bit-not
Implement bit-and-not
Merge pull request #66 from patrickgombert/remove-old-test

Remove vary-meta test from persistent-map-test