example.xlsx updated but loadspreadsheet.py NOT, so dont expect this to work
slight change to spreadsheet, not sure what
it works with the new spreadsheet format
Merge branch 'develop' into remaining-apis
removed overwrite protection for spreadsheet -- users can be careful :)
re-removed dependency on numpy
oops removed too much before
actually removed spreadsheet overwite; redoing logic of options etc.
minor cleanup
about to change the way results are calculated
split results code into calculation and plotting parts
wrote an efficient quantile function
cleaned up files and combined spreadsheet files
working with new version of plotting code
it works, but the quantiles are so wrong its not even funny
fixed bug with how programs are read in
fixed quantile calculations, but something weird happening with the data
working on quantiles, and fixed M.hivprev problem Roo pointed out
working! a little buggy internally but  working
fixed condom efficacy bug in model.py