Add general world timer events
Added semantic timer events again and separate event types
Support for allowing blocks to drop different items (or quantities) based on the tool damage type that was used to break it.

Also fixed a bug in serialization of MappedContainer fields with null values.
Make the headless server load the game manifest of the previous game.

This fixes issues with swapped block types after a game reload.
Fix NPE in CreateGame screen when modules are deleted
Fix privileges for ogg streaming sounds
Merge PRs #1333 and #1334 by @msteiger - sound asset fix and NPE hardening
Merge PR #1331 by @MarcinSc - tool effect on block drops
Add midday/midnight constants to WorldTime and add unit test
Rename WorldTime.TICK_RATE to TICK_EVENT_RATE
Merge PR #1324 by @msteiger - more time events
Change world time start from dawn to midnight
Merge PR #1336 by @msteiger - time tweaks
Use the inheritence cache in all getElementStyle methods.

Reduces unnecessary object allocation.
Update readme - new modules and credits update
Separate celestial events into new package
Climbing improvements
Extract celestial model into it's own class
Merge PR #1340 by @meniku - climbing improvements
Readd the old ladder (dug out of the legacy branch)