Fixes secbot hunting, stunning and arresting maintenance drones that attack them. Secbot won't hunt them anymore, just like with silicons. Fix is done by adding a assess_threat() proc in simple_animal/drone that returns -10 (similar to silicons)
Fixes a runtime with flashes when they burn out without user, now they'll display the burn out message from the src instead.
Fixes some problems with the mime outfit sprites and changes the sprites for the bowler hat, money bag and unmined uranium.
Merge pull request #5306 from Aranclanos/flashruntime

Flashes runtime fix
Merge pull request #5300 from phil235/DroneArrestFix

Fix for #5281
Merge pull request #5311 from TZK13/Minor-Sprite-Changes

Sprite changes for the mime outfit, bowler hat, money bag and unmined uranium
Merge branch 'master' of https://github.com/tgstation/-tg-station into whizzard

Conflicts:
	icons/mob/head.dmi
	icons/obj/clothing/hats.dmi