Add action const POP_AND_REPLACE

[bifrost]

I needed a way to change the scene stack [a, b, c] -> [a, d] so swipe BACK action natural went from scene d to a. It is not possible with existing actionConst in one go. Therefore I had to create the new actionConst POP_AND_REPLACE that combine BACK action with REPLACE action, where popNum is optional and default 1.

[mention-bot]

@bifrost, thanks for your PR! By analyzing the annotation information on this pull request, we identified @joenoon, @zxcpoiu and @BANG88 to be potential reviewers

[linonetwo]

Can you release it on npm? Badly need it!

[Naoto-Ida]

+1 would be a great addition for what I'm developing right now :)