Refactor out copied movement code.  Add flight mode.
Fix the FLIGHT enum name to be consistent with the others.
Fix bugs related to rendering items in a slot that have bad data. Fix EntityRef.copy() output.
Disable config button if no world generator is selected

Fixes #1189
Make modules respect snapshots
Merge #PR #1192 from @msteiger: Fixes #1189 - world config button vs empty world gen selection
Merge #1190 from @porl
Merge pull request #1188 from Josharias/InventoryUIFixes2

Fix bugs related to rendering items in a slot that have bad data
Merge #1185 by @Josharias - flight mode / movement tweaks
Update doc for new flight mode, update credits
Version tweak for gestalt-module to use a recent snapshot. Needs to go back to normal when the gestalt build job is able to do regular releases again.
Add new module to doc lineup + one more credits entry
Mark launchers as executables
Added a configuration setting to either disable (<= 0) or set the frame limit to something other than 60.
Merge #1201 from @neoascetic - mark launchers as executable
Update credits