week calendar print issue on Firefox

[houjie1979]

this happens on v1.2.3-pre and v1.2.2.
On firefox(43.0.4) testing print preiview on weekcalendar_full_demo.html
the border lines of time-header-cell do not consistent with time-slot row.
in fact, when you try zoom on Firefox, you'll see this issue. This is not a blocker. But it still exists in print action, which will be a major blocker to use week calendar.
I have to swich to to IE11 or Chrome for print operation, which're ok for print.

[houjie1979]

another minor issue on v1.2.3-pre and i put fix here.
on _scrollToHour : function(hour) function, the last else branch:
else {
//slot = hour - self.options.businessHours.start
slot = hour - self.options.businessHours.start-1;//fix code. index from 0
}