[Input] Add description to chemkin input files

data/inputs/air.inp

@@ -1,3 +1,5 @@
+! Ideal gas properties of air. Includes several reactions among
+! the included species.
 ELEMENTS
 O  N  AR
 END

data/inputs/argon.inp

@@ -1,3 +1,5 @@
+! Pure argon phase. Thermo and transport properties are taken
+! from GRI-Mech 3.0.
 ELEMENTS
 AR
 END

data/inputs/h2o2.inp

@@ -1,3 +1,4 @@
+! Hydrogen-Oxygen submechanism extracted from GRI-Mech 3.0.
 ELEMENTS
 O  H  AR
 END

data/inputs/silane.inp

@@ -1,3 +1,5 @@
+! Source unknown. Data originially added by Dave Goodwin in an early
+! version of Cantera.
 ELEMENTS
 SI H HE 
 END

data/thermo/nasathermo.dat

@@ -1,5 +1,3 @@
-THERMO NO_TMID
- 300.0   1000.0   5000.0
 !
 ! This is the NASA thermodynamic database, which is available for download
 ! from http://www.galcit.caltech.edu/EDL/public/thermo.html. The original 
@@ -14,6 +12,8 @@ THERMO NO_TMID
 ! Report TM-4513, October 1993.
 !-----------------------------------------------------------------------------
 !
+THERMO NO_TMID
+ 300.0   1000.0   5000.0
 Electron gas      L10/92E  1.   0.   0.   0.G   200.000  6000.0005.48579903-04 1
  2.50000000E+00 0.00000000E+00 0.00000000E+00 0.00000000E+00 0.00000000E+00    2
 -7.45375000E+02-1.17246902E+01 2.50000000E+00 0.00000000E+00 0.00000000E+00    3