[ck2cti] Keep full precision of NASA 9-coefficient thermo data

The 9-coefficient format keeps 10 digits for each coefficient, compared to 9 for
the 7-coefficient format.

Cherry-pick of trunk r3256.

git-svn-id: https://cantera.googlecode.com/svn/cantera/branches/2.1@3257 02a645c2-efd0-11dd-984d-ab748d24aa7e