- added else branch to conditional actions

- implemented history for any object extending BaseClass (i.e. almost any)
- added distance() calculation method to base class
- Button "edit JSON" in Action Lists now hidden by default, can be enabled in plan properties

- fixed bugs:
    - updating json of DisplayText was not working properly
    - log output in Tile.isFreeFor was broken

.gitignore

@@ -5,6 +5,7 @@
 *.cu
 *.routes
 *.trains
+*.history
 /backup
 /bin/
 /Debug/