how was this thing working earlier?
simplification
fix the display of mouse coordinates
fix angle display
add fundations for mutiple worlds per exercise
delegate hashCode for consistency
Merge pull request #140 from polux/pull_request

Small fixes and simplifications
let's be explicit
allow universes to use winning conditions that are not based on world's equality
Merge pull request #141 from polux/configurations

Add the fundation for mutiple worlds per exercise