Add Alpha Channel as optional value for color keys about trenchbroom HOT 2 OPEN

The color1 and color255 KV types, which aren't properly supported by Trenchbroom yet (relevant issues #4293, #1048) allows any arbitrary number of additional values after the three color values to be manually added (that's how Half-Life's light entities handle brightness, and would work here for alpha). Does Trenchbroom strip these when using the color picker? They should be kept.

On a related note, I'd imagine it'd make sense to allow the model() key's alpha parameter to take a color1 or color255 KV as input, and assume the fourth value is alpha.

from trenchbroom.

Perhaps TB might read these values, but it certainly doesn't appear to use them when trying to create a new map. I can't verify whether they're being stripped from maps which actually do contain them or not, just that the smart editors don't pick up on them.

from trenchbroom.