add: Array.prototype.contains() polyfill

del: lib.contains()
Firefox Nightly has Array.prototype.contains
https://twitter.com/jdalton/status/514502715876315137
fix: 2nd arg in Array.prototype.indexOf polyfill
fix typo
2nd arg in Array.prototype.lastIndexOf polyfill
add: generic Array.contains
use array contains everywhere
build 0.6.0