[Python] Specify python executable to be used in shebang line for scripts
[Python] Specify python executable to be used in shebang line for scripts

This fixes a bug in the Windows installer where the path to python.exe on the
machine where the installer is built is used, and also allows us generate
different shebang lines for the Python 2 and Python 3 modules.

Fixes Issue 247.

git-svn-id: e76dbe14710aecee1ad27675521492cea2578c83@3355 02a645c2-efd0-11dd-984d-ab748d24aa7e

Cantera/cantera-svn,Cantera/cantera-svn,Cantera/cantera-svn,Cantera/cantera-svn,Cantera/cantera-svn,Cantera/cantera-svn