[lmi] Spreadsheet tools for validation

[Greg Chicares]

Two spreadsheets, useful for validating certain life-insurance
calculations, will appear in our "ftp" area here:
  http://savannah.nongnu.org/files/?group=lmi
once I've uploaded them and they've propagated to the mirrors.
Both were saved, using openoffice.org 'calc', in 'excel 97' format
so that people who are forced to use a proprietary spreadsheet
program can load them.

'validate_gpt.xls', the protoplast, performs guideline-premium
calculations from first principles using the techniques in Eckley,
TSA XXXIX, page 18:
  
www.soa.org/library/research/transactions-of-society-of-actuaries/1987/january/tsa87v395.pdf

'validate_commfns.xls', derived from the former, provides the
"results imported from a spreadsheet" referred to on line 614 here:
  
http://svn.savannah.gnu.org/viewvc/lmi/trunk/commutation_functions_test.cpp?annotate=4766&root=lmi&pathrev=4766