Special case chemkin names for inert colliders (don't append index).
Special case chemkin names for inert colliders (don't append index).

This is to make the chemkin files look the same as those from RMG-Java,
i.e. "Ar" is just called "Ar" and not "Ar(16)". Perhaps in the long run 
this should be reverted, but for now the compatibility with all my chemkin
input files is vastly preferable :-)
enochd/RMG-Py,faribas/RMG-Py,comocheng/RMG-Py,chatelak/RMG-Py,comocheng/RMG-Py,nyee/RMG-Py,nyee/RMG-Py,KEHANG/RMG-Py,enochd/RMG-Py,chatelak/RMG-Py,pierrelb/RMG-Py,faribas/RMG-Py,nickvandewiele/RMG-Py,nickvandewiele/RMG-Py,pierrelb/RMG-Py,KEHANG/RMG-Py