* Allow Custom Gauges to fully use parent type colors
#6670 allowed for custom coloring of HUD gauges, so this PR follows that up with fixing a few edge cases where mods with custom gauges that are linked to parent gauge types accurately reflect the color of their parent gauge type in both the new saved HUD file and the in-mission HUD.
This ability to link color to parent gauges for custom gauges the player cannot edit is what the behavior has always been, so this PR does not change any expected behavior it simply ensures that the new HUD updates and various combinations of table entries for `Config` are all robustly accounted for. For example, in FotG we have multiple non-configurable custom gauges all tied to the center reticle, so if the player changes the color of the center reticle all the custom gauges set to that type also automatically change color.
Tested and works as expected.
* appease clang
* one more clang
* clang needs to calm down
* instruct clang to be calm
* fix comment typo
FSO doesn't appear to use this any longer. And even when it was enabled the
requirements made it largely useless anyway. Removing to clean up cfile a
bit and so we don't have to keep maintaining it.
Mike Nelson