Make text in timelines not selectable

Timelines can look a bit wonky if users accidentally select text as they scroll through.

Adding onselectstart='return false;' to the timeline-wrapper div in the views theme fixes this for IE (well, needed for IE8 at least)... and adding this css should fix it for the rest:

div.timeline-wrapper {
-webkit-touch-callout: none;
-webkit-user-select: none;
-khtml-user-select: none;
-moz-user-select: none;
-ms-user-select: none;
-o-user-select: none;
user-select: none;
}

I don't mind rolling a patch if there's any interest in committing this.