Don't use enums for things loaded from FS / dynamically changed

[stingray300k]

See comment here:

BlendRadiant/blendradiant/prefs.py

Lines 74 to 76 in fe13621

	# TODO having this as an enum is actually wrong because they're saved as
	# ints, so whenever the directory changes it will mess up its meaning...
	# somehow only use enum for UI but save as str

Not sure how to do this. Last time I checked there was no way for Blender addons to listen to "events" such as the user selecting something in a drop-down menu. One option would be an additional button that needs to be pressed to "lock in" one's selection, but that is outrageously stupid.

[stingray300k]

https://blender.stackexchange.com/q/16511 should be helpful, especially the answers further down. EDIT: Or maybe not, this is just stuff I already knew...

[stingray300k]

https://blender.stackexchange.com/q/110514 is better (the answer is trash, truth is in the question comments). And I already did it this way for entity classnames, anyway, cf. my own code. But that uses custom UI, which I don't yet have for preferences. Should be possible though: https://b3d.interplanety.org/en/add-on-preferences-panel/