Synchronized pdf wording to that in the beta version
limit all reported values to two significant digits
preserve full precision of user input if input units same as output units
standards: retain original representation if outunits same as standards units
sort by has-overages, then alphabetically
bugfix: sort order for chemicals
do not use scientific notation in canonical names
bugfix: crashes when comparison=10.0
bugfix: eliminate crash in _render_sample_info due to None value
Merge branch 'alpha/update-pdf' into release/alpha