Immersive Cavegen

- Fixed brown spiders spawning in the nether, the end and the oceans

- Added an option to turn off cave spider spawners in mineshafts

- Fixed a forge worldgen patch not applying when this mod runs, this should hopefully improve mod compat

- Added an option to make cave spider spawners always spawn, making for hardcore mineshafts

- Added config options to allow manually setting indicators (IDs) for entities

- Replaced the default spawn eggs for this mod's mobs with custom spawn eggs and put them into the mod's tab, as some people were reporting not seeing them due to a vanilla spawn egg bug

- Changed glowslimes' colors a bit to make them easier to differentiate from normal slimes, as requested