EXP-1181 FIX As a designer, I would like to specify default floater positions...

EXP-1181 FIX As a designer, I would like to specify default floater positions using relative coordinates
floaters given specified positions will stay in that location
floaters that stack will treat that as a specified position
moving any floater will switch to relative positioning mode
cleaned up some XUI where widgets were relying on a default height of 10 pixels