Auto slide API

Hi Hakim,

the new release included a nice new auto-slide control. However, the API for navigation and reading state was not updated. This is a bit inconsistent, because users can navigate using functions as ```next()```, ```toggleOverview()```, etc. but weren't able to pause/resume the auto-slide mode.

I extended the API to support similar functionality for the new control as has already been provided for the old navigation controls. Furthermore, I think it is important to also fire events when auto-sliding is paused or resumed (one important use case could be to pause/resume media files when the  auto-slide control is played), so I added the new events ```autoslideresumed``` and ```autoslidepaused```.

Hope you find these changes useful and would love to see them merged.

Thanks 
Raj