[Quality of Life] Additive bonuses

[praiseskeltal]

For cases where multiple separate bonuses (or penalties) could be applied (d20+1+1), stack bonuses

[DLvalentine]

Would change the logic in #roll a bit, and maybe even the #format function.

Would need to use regex or something to match all of the + or -, and reduce them all down before doing the math against the total. And then make the decision to either itemize the stacks, or display them combined.

We'll playtest this for value and see if it is really needed.