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
Merge branch 'gromacs-var-decimals'

Change-Id: I8feab596f4b124dc4486b26971e9b8fd3efbe685