More icons. At last!
Adding .directory to gitignore.
Delete .directory
Fix an item duplication glitch
Various fixes
Chargen updates
Fix an AABB assert for loading empty exterior cells
Don't crash when trying to delete a reference that doesn't exist anymore
Use the non-accumulation root's parent as the accumulation root

This relies on the non-accumulation root not being the skeleton root. I haven't
found an instance where this isn't the case.
Use a smaller static geometry size for interior cells
Fix actor stepping
Remove unused functions and parameters
Merge remote-tracking branch 'scrawl/master'
Merge remote-tracking branch 'kcat/misc-cleanup'
Merge remote-tracking branch 'sirherrbatka/icons-svg'

Conflicts:
	.gitignore
Refactored loading screen

 - Add loading progress for data files, global map, terrain
 - Refactored and improved cell loading progress
Renamed Terrain::Terrain to Terrain::World to make VC happy
Replaced log2 to make VC happy
Fix the water being affected by fog on the map
Avoid a hack to play the underwater sound properly