[RFC] Started initial work on sendMulti

This is just my idea of how the method should look. It should work serially for all adapters and the event system should still be called. Now the trick is to override this method in adapters that support parallel requests... Possible solution for #31 

Feel free to comment or criticize. I am not hung up on this being the way to do it.
Not sure what is the best option here. Allowing to pass an array of objects and/or strings would improve the flexibility so, I would say why not :)