Init multiple editors without html option: textarea contents could get overridden

Actually I have 3 textareas, with different ids and different texts inside. However when I instanciate wym editor every textarea content gets filled with the first textarea content. It does work well with 1.0b3 but not with b5
`var wym = this;`:
This looks cleaner and more easy to understand than relying on being passed the editor as the argument.