Cleaned up Managers, Updated references

* Cleaned up AirbendingManager, updated references for abilities air
* Cleaned up FirebendingManager, updated references for abilities fire
* Cleaned up WaterbendingManager, updated references for abilities water
* Cleaned up EarthbendingManager, updated references for abilities earth
* Cleaned up ChibendingManager, updated references for abilities chi
* Cleaned up BendingManager, updated references for classes
Merge pull request #27 from jacklin213/bugfix

[BUGFIX] Fixed NPE in TempPotionEffect, Task #40 Error - Bloodbending, Task #23 NPE - IceSpike Error - Combustion, NumberFormatException - Commands
Merge pull request #26 from jacklin213/main

Cleaned up Managers, Updated references