New option: Escalation by 1

[PsyDev]

Suggestion Idea:
I suggest we add a new option to the escalation possibilities: Escalation by 1.

Specifics:
You start with +4 for a cash in, and each cash-in is +1, so 5, 6, 7, 8, etc.

Why it is needed:
I find there are some maps where the big jumps in cash ins might not be as appropriate. Sometimes a slower-developing game with respect to cards is preferable.
Also, it just makes the game a little different. It's nice to have a variety of options in my risk games, I find. This slows down the pace of the game and makes it so that the huge cash-ins don't come until a few turns later. It also makes it so that card escalations grow more slowly and steadily instead of quick and jumpy. Don't get me wrong, I love escalating +5 games too, I just like this other option sometimes as well.
Also, for what it's worth, this feature is included in Hasbro's "Risk II" PC video game. Therefore, it has some "street cred", if you will.