* fixed a few crashes related to unusual effect levels
* added haste and fatigue combat functionality
* added some cleanup to avoid hangover unstackable items
* capped the slowdown from fatigue at 5 minutes digging time
* (despite the above, if a tool has a longer time set in definition,
that still works)
* removed an unused "global" variable
* added a way to have a damage modifier relying on type instead of flag
* added Slow Falling
* added Levitation
* added Health Boost
* added Absorption
* Fixed some effects not being replaced correctly with higher levels
* Implemented an old FIXME (MTE 5.3.0 fixed underlying bug)
* Added a way to obtain an approximate level of effect from factor
* Added effect level to HUD under the icon
* Added effect timer to HUD under the icon
-heal subcommand to the /effect reimplemented
-healing_func() from old API standardized, included in new API
-(the last point is due to it being substantially different from others)
-fixed a few bugs, potential crashes
-fixed incorrect withering effect progression
-standardized variable naming
-improved the /effect command, allowing to use effect levels
-fixed a bug in level-to-factor conversions
-renamed effect icons to follow the new convention
- added a `register_effect()` function
- added the withering effect
- registered all the old effects under the new API
- unified effect names
- updated the main effect checker to use the new API
- changed some hardcoded values to support the unified effect naming
- added new namespaced metadata effects strings
- added support for legacy effect player metadata
- potions are still using the old effects API
- added glue between old API calls and the new API
- renamed the effect icons to support the unified effect naming
supports "level" now, bad omen > 1 means extra wave additionally
the playername is saved in the event object now for later access
and events can be made exclusive to a certain radius now.
