changed "float" to "double" in thermo.pxd
changed "float" to "double" in thermo.pxd

in conjunction with my previous commit, I believe this closes #20

enochd/RMG-Py,nickvandewiele/RMG-Py,chatelak/RMG-Py,nyee/RMG-Py,comocheng/RMG-Py,pierrelb/RMG-Py,nickvandewiele/RMG-Py,enochd/RMG-Py,pierrelb/RMG-Py,nyee/RMG-Py,faribas/RMG-Py,KEHANG/RMG-Py,comocheng/RMG-Py,KEHANG/RMG-Py,faribas/RMG-Py,chatelak/RMG-Py