Added some code to deal with variable decimal places
Added some code to deal with variable decimal places

The GROMACS file format supports variable decimal precision, follow
their instructions to infer separation between position components.

Change-Id: If868ba8ebfd9dd50a3a69b8fcbc741ceb13b6ecc

OpenChemistry/avogadrolibs,OpenChemistry/avogadrolibs,ghutchis/avogadrolibs,ghutchis/avogadrolibs,OpenChemistry/avogadrolibs,ghutchis/avogadrolibs,wadejong/avogadrolibs,ghutchis/avogadrolibs,wadejong/avogadrolibs,OpenChemistry/avogadrolibs,wadejong/avogadrolibs,wadejong/avogadrolibs,OpenChemistry/avogadrolibs,ghutchis/avogadrolibs