Possible fix voor #54

I fixed an issue with going to the next day. It doesn't seem to be related to getFirstVisibleDay but to goToDate. Not sure if it fixes the original issue.

Author: Jens Claes

library/src/main/java/com/alamkanak/weekview/WeekView.java

@@ -1359,7 +1359,8 @@ public void goToDate(Calendar date) {
         today.set(Calendar.SECOND, 0);
         today.set(Calendar.MILLISECOND, 0);
 
-        int dateDifference = (int) ((date.getTimeInMillis() - today.getTimeInMillis()) / (1000 * 60 * 60 * 24));
+        long day = 1000L * 60L * 60L * 24L;
+        long dateDifference = (date.getTimeInMillis()/day) - (today.getTimeInMillis()/day);
         mCurrentOrigin.x = - dateDifference * (mWidthPerDay + mColumnGap);
 
         invalidate();