Cycling back with shift+enter

[rohantalesara]

Added the commands "shift+enter" in the key maps, and made a class to handle jumping to previous highlight. More changes need to be made for the feature to work completely.

[ice9js]

So cool that you're taking this on! It's probably number one on the list of features I'd like to implement.
Before merging anything though, could you explain what your plan is to make the whole of it work ?
Also, should you want to merge before the whole thing is finished, I'd personally opt for not merging the keybindings just yet - just so it doesn't mess with anyone else's setup.