zoomslider sets only sporadically

zoomslider does not update its display on zoom level change

The buttons for setTime(date) set the date to 1 year back, ie 1775 instead of 1776.

testdata:

• failsafe loop works but ugly

testdataeons

• failsafe loop 3rd time 6000 count
• bounds object not set correctly in testdata
• this data range has not yet been implemented

• after recalcBounds, set those bounds into the timeline, ie begin, end