Improved Console and fixed .display(..., double batt) bug

The console has many extra functions and an improved help screen. It
also accepts names as well as numbers for input.
Example: /periode 3maanden
/scherm binnenluchtvochtigheid

It searches for keywords, so exact naming is not necessary.

LangsteDroogstePeriode.java

@@ -15,7 +15,7 @@ public class LangsteDroogstePeriode extends Grootheid{
         langstePeriode = StatisticsCalculator.langsteDroogstePeriode(list);
     }
     
-    public void display(String periode, boolean knop1, boolean knop2, short batt){
+    public void display(String periode, boolean knop1, boolean knop2, double batt){
         GUIboard.writePageToMatrix("Langste Droge Periode", langstePeriode + "", periode, knop1, knop2, batt);
     }