Adding an updated notebook manager implementation for ipython 2.x

[gf-atebbe]

I don't know if you're interested in accepting this on a separate branch from master but I used the simple notebook manager as a reference and implemented the notebook manager class for ipython 2.x. Testing has been a bit minimal still and there's plenty of room for improvement since I overrode some methods in the base class that I probably didn't have to but I figured its a start....

[davidbrai]

@gf-atebbe thanks for the pull request. I'll review it in the next few days!

[fatlotus]

Any progress on this issue?

[davidbrai]

Hi @fatlotus, unfortunately I didn't get to reviewing this, I'll do my best to find some time and review this