- manual block resize: round value to closest column/row
- set min height for a block so automatic resize won't make
a block smaller than the height the user selected on view edit
- no float grid: save the new position of all blocks
when gridstack moves them to fill empty spaces
- no need to consider the horizontal margin when
setting the column number for a block
- don't set min-height for collapsible blocks on display

behatnotneeded
Change-Id: I4a890a83ed76df523a2904a9776cf7f1076d3cb2