[Design] # of hours in the calendar view

[Alec Flett]

I've just checked in a change that will let people fiddle with the 
number of visible hours in the calendar.

There are two modes:
1) The height of an hour is based on the current font, so that an hour 
should hold two lines of text with a few extra pixels for margins
2) The height of an hour is based on the current window size and a pref 
indicating the number of hours. In this mode, you could say "make 7 
hours be visible" and from then on, no matter how big or small your 
window is, exactly 7 hours will fit vertically.

You can fiddle with these settings in the View menu - View -> Visible 
Hours. Its not clear if this is the final UI for this feature, but it 
will let people play with it.

Please post feedback about what setting you like best on this thread.

Alec