Modified how to height is defined. it's used script/Method now to define the height of the Blocs.
The value expected is 0 < value < 1, it will be commited a test at testPlanningBox to validate the change. 



git-svn-id: https://svn.erp5.org/repos/public/erp5/trunk@17577 20353a03-c40f-0410-a6d1-a30d3c3de9de