Disabled sky mode selection
Updated ChangeLog
Automatically determine scene directory when using -render (fixes #98).

Amended by llbit:
- use File.isFile instead of File.exists
- fixed NPE error introduced by pull request
Made line endings uniform in file
Fixed error in console output
Merge branch 'master' of github.com:llbit/chunky
Fixed error in cloud height field listener

- changes in the cloud height field affected ray depth insteady of cloud height
Store ray depth as a global setting

fixes #100
Set log level to WARN
Update progress after octree and quadtree loading
Removed library unpacking messages
Have Chunky#run wait until rendering is complete before returning to avoid premature System.exit(0).