Remove event by fn, checks && id

[agmcleod]

howler.js/src/howler.core.js

Line 1560 in 7547703

if (fn === events[i].fn && id === events[i].id) {

Was having a look over the code to see if I can remove an event just by ID, and I think I see an issue here. Given that it lists id as optional, but checks it against the event, as well as the function, I don't think one can remove an event by using the function parameter at all.

A simple fix here would be to swap it to an ||. Or one can change it to:

if (fn === events[i].fn && (!id || id === events[i].id))

To cover what the API says it will do :)

[goldfire]

This is partially intended behavior. If you passed an ID into on, then you need to pass an ID into off because if you don't pass ID into on it is a different type of listener. However, I just pushed a commit that allows you to cancel like sound.off('play', id); instead of having to pass the function as well.