Add in a mop that uses oldmopping

[Lady Birb]

I thought puddles were inherently slippery when entering or exiting them?

The thing with old mopping that made it more fun was:

1. With the new system puddles only slip you when you enter or exit them, while old mopping made every wet tile slippery
   
2. New puddles are very visible, while old wet floors were only visible by the tile occasionally shining, making it possible to not notice that a tile was wet
   

The fluids system also made cleaner grenades less fun, as they used to make all the floors they cleaned wet, and thus slippery, but they don't make tiles wet anymore.