Alpha 11 release-450

Bug fixes

 * Fixed bug that caused bad performance when building tall structures.
 * Fixed crash placing freestanding walls when a column location could not be found.
 * Support connecting two buildings with a freestanding wall.
 * Only user placed ladders can be removed from the top. This helps to prevent hearthlings from stranding themselves on the roof.
 * Changed storage filters to account for flour and wheat.
 * Fixed UI error when promoting a hearthling and closing the dialog too fast.
 * Prevent the ‘None’ checkbox on a storage filter from becoming stuck.