Environment agnostic nextTick polyfill
created at Aug. 29, 2012, 7:56 p.m.
Map collection as specified in ECMAScript6
created at May 17, 2013, 10:24 a.m.
Set collection as specified in ECMAScript 6
created at Oct. 12, 2013, 9:45 a.m.
WeakMap collection as specified in ECMAScript6
created at Oct. 24, 2013, 2:42 p.m.
ECMAScript 6 Symbol polyfill
created at Nov. 15, 2013, 12:08 p.m.