indexOfListener now always uses manual method.
indexOfListener now always uses manual method.

Also removed useless comments and the checking for a native
Array#indexOf.

Wolfy87/EventEmitter,Wolfy87/EventEmitter,Olical/EventEmitter,oculus42/EventEmitter,modulexcite/EventEmitter,Olical/EventEmitter,modulexcite/EventEmitter,Olical/EventEmitter,oculus42/EventEmitter