Bidirectional scrolling in timeline - make horizontalScroll and verticalScroll work together (#3162)
* Bidirectional scrolling.
Make horizontalScroll and verticalScroll work together.
* Fix delta variable declaration
Using ?: operator
* Remove notice about vertical and horizontal scroll conflict
There is no sense considering #3162
<td>This option allows you to scroll horizontally to move backwards and forwards in the time range.
Only applicable when option <code>zoomCtrl</code> is defined or <code>zoomable</code> is <code>false</code>. Notice that defining this option as <code>true</code> will override <code>verticalScroll</code> scroll event but not eliminate the vertical scrollbar.
Only applicable when option <code>zoomCtrl</code> is defined or <code>zoomable</code> is <code>false</code>.