fpspreadsheet: More calculation of rpn formulas, add TestCalcRPNFormulas cases to formulatests. Boolean results not working yet. And implementation only for BIFF8, so far.


git-svn-id: http://svn.code.sf.net/p/lazarus-ccr/svn@3249 8e941d3f-bd1b-0410-a28a-d453659cc2b4