[Open Assets] Retro Bosses + Maces and Chains 2.4

This update brings a couple of bugfixes, plus UDMF support!

CHANGES:

• Added UDMF Support!
  • Every boss can now have its own pinch phase trigger, death trigger, "victory" trigger, etc.
• Cleaned up the code to be more in-line with my other addons.

BUGFIXES:

• Fixed a bunch of interpolation issues introduced in SRB2 v2.2.11.
• Fixed another C stack overflow error involving 2.0 Brak's goop.

This update brings a couple of improvements to how 2-player bots impact gameplay:

QUALITY OF LIFE IMPROVEMENTS:

• 2-player bots can no longer grab or control missiles fired by 2.0 Brak. This should make the fight a little more fair when playing as Sonic & Tails. It also fixes a bug where the player can get stuck on the missile if a 2-player bot is also riding the same missile.
• 2-player bots can also no longer control spinning chains. This prevents chains from accelerating twice as fast as they should when a player and a 2-player bot are on the same chain.

Special thanks to Widu Midu on the SRB20YA Discord server for discovering the 2.0 Brak missile bug!

This update fixes a bug where the hanging chains could not move at all.

This isn't a big update, but it's one I felt was needed.

QUALITY OF LIFE IMPROVEMENTS:

• Maces and chains now move and are visible ONLY if a player is nearby. This feature has been inherited from 2.2 to reduce lag on devices with slower CPUs. It can be turned off by checking the "Repeat Midtexture" parameter in the mace/chain spawnpoint's control linedef.
• Added the "then" keyword to numerous parts of the code to make it more readable.
• Got rid of some commented out code to de-clutter it.

For gameplay reasons, 2.1 Metal Sonic can now be affected by any projectile (and aimed at by Fang) in his "floating" state.

Fixed a bug where Brak's flame shots, after colliding with the ground, could hurt fire-resistant players (flame shield, elemental shield, etc.).

CHANGES:

• The 2.0 Egg Mobile now bounces off of the player instead of going through them in its "panic mode", making it more accurate to its behavior in 2.0
• All legacy sound effects have been replaced with their modern SRB2 counterparts, so modders don't have to include the legacy sounds in their mods

BUGFIXES/QUALITY OF LIFE IMPROVEMENTS:

• Some bugs involving chains were addressed:
  • Fixed a bug where the player could get stuck in the CR_MACESPIN carry type if a chain disappeared while the player was riding it
  • Fixed a bug where the player could get out of their spinning state if a spinning chain went through the level geometry
• 2.0 Brak can now be affected by both sector gravity and global gravity, instead of just the latter
• Added validity checks throughout the code to reduce the chance of errors occurring

Changes:

• The 2.0 Egg Slimer now goes into its pogo state if there is no NiGHTS axis present in the current level. The original behavior (dying instantly) can be restored by setting the map Thing's parameter to 1.

Bugfixes/Quality of Life Improvements

• Both MapThingSpawn hooks for the 2.0 Egg Slimer have been merged into one.

This small update fixes a bug involving 2.0 Brak's goop, among other changes.

Changes:

• Every level can now be chosen in a multiplayer game without needing to complete it first!
• Every (uncommented) instance of "!=" has been replaced with "~=" to stay consistent with my other addons

Bugfixes:

• Fixed a C stack overflow error that would occur when 2.0 Brak's goop tried to stick to more than one player at a time

This update mainly focuses on bugfixes and other changes.

Changes:

• The "Resource" and "Example" PK3s have now been merged into one - This should prevent users from trying to load both at the same time and encountering numerous unintended bugs.
• Added text for map Thing flags in Zone Builder - You can now see what each flag does (ex. "End level on death" instead of "Special")!
• Redid the way jet fumes are spawned and positioned - The code is now slightly less redundant!
• Merged the Egg Slimer's "gib" spawning code into one action - The code is now shared between the two versions (2.0 and 2.1); Updating is not necessary, but highly recommended!

Bugfixes/Quality of Life Improvements:

• 2.1 Metal Sonic should no longer disappear in netgames
• Simple Mode:
  • 2.0 Brak missiles can now be turned with the "Move Left" and "Move Right" controls (only in Simple Mode)
  • 2.0/2.1 chains can now be turned left and right without bugging out