include perf boost as well as ECMA6 detect for include or contains

Based on the proposed polyfill for ECMA6 for `String.prototype.contains()`

http://wiki.ecmascript.org/doku.php?id=harmony:string_extras

using not equivalent to `!==` instead of greater than `>` gets a performance boost according to
http://jsperf.com/string-contains

as well as add the detection if `String.prototype.contains()` exists then map `include()` to that