Generalized the concept of GameTimer to PausableTimeout and PausableInterval.
Added score for shooting animals.
Refactored onShotCallback to be given to animals as argument.
Also changed signature of the onShotCallback.
Refactored animalClick to layerClick.
Implemented date and points counter visualizations.
Implemented point counting for killing animals.
Fixed bug with positioning the points text.
Fixed bugs in pausable timers to ignore unPause before the timer is started.
Fixed deerhuhn.keys.js according to linter messages.
Added utility addEvent supplying a comfortable way of using attachEventListener cross-borwserly.
Implemented ammo display and reloading.