Fix another case of global variable use
Fixed link to the documentation
Do not call `obj.destroy()` early in `me.game.remove()` (the removal may be deferred)

- Fixes some questionable uses of `me.game.remove()` inside callbacks.
- Calling `me.game.remove()` from a callback with `force == true` or `me.game.removeAll()` will NEVER be safe. Update docs to include this warning.
Merge branch 'master' of github.com:melonjs/melonJS