better way to calculate good window size.
better way to calculate good window size.

Instead of blindly use 1/3 of zone, now it will account shelf sizes
and will try some proportions before giving up.



SVN revision: 40179

FlorentRevest/Enlightenment,tasn/enlightenment,rvandegrift/e,rvandegrift/e,tasn/enlightenment,FlorentRevest/Enlightenment,FlorentRevest/Enlightenment,tasn/enlightenment,rvandegrift/e,tizenorg/platform.upstream.enlightenment,tizenorg/platform.upstream.enlightenment,tizenorg/platform.upstream.enlightenment