adding the hide all but cell method

I had a use case for the v2.0 Its On Me app where ...  when you slide open one cell , it was required that any other open cell closed.  I solved this use case by making a multi-purposed method that you could call from anywhere that resets any cell that isn't the cell you pass in.  Pretty self explanatory.  Thanks for the cool pod dude ! 

FYI, i overwrote in a base cell class in my version , I was un-able to overwrite as i am commiting below due to pod overwriting being a pain.  So please run this before for any typos etc ... My base class version works perfectly .