cleanup
one more cleanup before I move stuff around to other files
factored out code to main_menu.lua
refactored gameplay out to world.lua
cleanup
moved world.lua (gameplay) to state subdirectory
moved gameplay specifics to state subdir. TODO they should really go into something like "state/gameplay/"
moved the gameplay specifics further down the tree
minor cleanup
Merge branch 'feature/issue/#14' into develop