fpspreadsheet: make sure that formulas are only recalculated when needed (in particalar only once after loading a file). Rename worksheet option soCalcAfterSaving to boCalcAfterSaving and assign it to the Workbook. (Add section "Incompatible changes" to wiki). 

git-svn-id: http://svn.code.sf.net/p/lazarus-ccr/svn@3478 8e941d3f-bd1b-0410-a28a-d453659cc2b4