Documentation re-org.

git-svn-id: http://osgbullet.googlecode.com/svn/trunk@367 52ec9183-9a46-0410-8497-359fc0c0ba5a
Remove unused "docs" folder.

git-svn-id: http://osgbullet.googlecode.com/svn/trunk@368 52ec9183-9a46-0410-8497-359fc0c0ba5a