Cell pad fixes

Hey there!

This is my first PR, but this project is awesome so far and i wanted to contribute

I made some changes/fixes/additions to the current cellPad and padHandler classes, theres still some work to be done with it, but i figured id shoot this off before I got too carried away with anything

I tested most of my changes with a quick padtest psl1ght homebrew i made here
https://github.com/jarveson/rpcs3elfs/  which reports things working still, and the analog button presses to be a bit more sane when changing

I tried to follow coding guidelines/style but if i missed or something needs to change, let me know!