This FormulaEvaluator patch contains:
1. All core classes complete, stable and tested.
2. Several Function classes completely implemented, stable and tested.
3. IMPORTANT: Very minor change in FormulaParser in HEAD (+ 4lines).
FormulaParser failed for UnaryPlus operations and UnaryPlusPtg was not being
created during parse(). This has been fixed looking at how UnaryMinus was being
handled. Please verify the fix is correct!!!
4. updated xdocs included in patch.
5. Automated test class included but needs a source file change to configure
for particular environment. This mechanism needs to be changed once the patch
is certified stable :) The test xls is added separately, not included in patch.