add changelog, edit examples, 3 new function

- New: reset initscreen timer:
LCDMenuLib_IS_reStartTime();
- New: start initscreen direct:
LCDMenuLib_IS_startDirect();
- New: get active Function ID:
LCDMenuLib_getActiveFuncId();
- New: a new menu element "back"
- Bugfix: remove some wrong code from the examples