Add Option to Only Generate Combos in Set Color Identities / Number of Colors

[GordonsKitchen]

For combos where a set commander is required, it would be good to have an option where we can tell the generator to only generate variants in a set color identity / identities. For a commander-required combo (excluding partners / backgrounds), it would always be the commander's color identity unless it can change it. I would envision this being maybe a checklist we can manually check what color IDs will generate and what ones won't. Might be good for shortcuts for # of colors as well. So for commanders with backgrounds, the max number of colors is 2, so anything generated with 3+ colors is automatically bad. We can just say "2 or less colors" and not have to worry about it. I'll put a brief checklist below.

1. Add a way for editors to specify color identities when editing / adding a combo.
2. Change the generator when identities are present to only generate variants meeting the color ID requirements. So basically, when it goes to generate variants, generate them and then check if that color ID is valid. If so, fully generate it for editors to see. Otherwise, discard it. If no identity is present, assume all work.
3. Add a way to specify # of colors when editing / adding a combo.
4. Change the generator when colors are specified to ensure variants are within that number of colors. I would do a checklist / drop-down box from 0 to 5 and we can check the maximum number of colors to use. The generator will make the variants, check to ensure the number of colors (which would just be the string length of the identity, except for C=0) is less than or equal to the selected value.

I would like to note that I do not want default behavior for this when a commander is selected, as that creates issues with partners, backgrounds, etc. This seems like the best approach to save some editor time sorting out bad variants.

[ldeluigi]

My only issue would be when wizards prints double colored backgrounds or something similar, which would mean finding and editing a lot of combos to allow one more color I guess

[ldeluigi]

Additionally, are there cases where variants with a partner allowed to have two more colors but not for any guild? I guess it's acceptable to assume there would always be a partner of the right color combination to complete the needed pie