[color] properly filter sources in drop-downs

[raphaelcoeffic]

Resolves #731

[pfeerick]

Did the trick for me AFAICT... no garbage entires, only L01 (which is defined), only telemetry entires that exist. Just need to poke around a bit more and wait for wimalopaan to give feedback also.

[pfeerick]

For what it's worth, I'm not seeing Time, Batt or Timers when in the source list on the INPUTS tab (or MIXES, although I don't think it is supposed to show up there), but are present when in logical switches, so that's good. Judging from Companion, Tele values are switches for the purposes of special functions - if so, that source list is good also.

[raphaelcoeffic]

For what it's worth, I'm not seeing Time, Batt or Timers when in the source list on the INPUTS tab (or MIXES, although I don't think it is supposed to show up there), but are present when in logical switches, so that's good. Judging from Companion, Tele values are switches for the purposes of special functions - if so, that source list is good also.

I'm using the same filter functions as the B/W targets, so that it should be consistent with them.