Removed stopPropogation, cancelBubble from term.js

Hi, I'm writing [cloud file manager](http://cloudcmd.io "Cloud Commander")
and using terminal, but it has no ability to run programs such **mc** or **vim**.
So I try adopt term.js to use it.

But I have a problem with cancelling event it **term.js**.
Listeners of Terminal is added to document, it's not  very good,
my listeners doesn't work because they are canceled in this code:
```
  if (ev.stopPropagation) ev.stopPropagation();
  ev.cancelBubble = true;
```

Is it realy needed?  Maybe there is some way to drop them?
Or add listeners to terminal element?

Thank you.