throw exception if via count is uninitialized

Author: Peter

core/src/main/java/com/graphhopper/util/ViaInstruction.java

@@ -42,6 +42,9 @@ public void setViaCount( int count )
 
     public int getViaCount()
     {
+        if (viaPosition < 0)
+            throw new IllegalStateException("Uninitialized via count in instruction " + getName());
+
         return viaPosition;
     }