table: Don't add spacing for rows/cols that only contain hidden actors
table: Don't add spacing for rows/cols that only contain hidden actors

When calculating the table dimensions, count how many rows/columns contain
actors that are visible. Then use that count when calculating width/height
and actor placement so as to not add extra spacing for hidden rows/cols.

Fixes: http://bugzilla.meego.com/show_bug.cgi?id=896

pwithnall/mx,pwithnall/mx,jonnylamb/mx,clutter-project/mx,jonnylamb/mx,clutter-project/mx,jonnylamb/mx,pwithnall/mx,clutter-project/mx,jonnylamb/mx,clutter-project/mx,pwithnall/mx