Project will move to github. Find this wiki page at the new address: https://github.com/cztomczak/cefpython/wiki/InnoSetupInstaller
Inno setup can be installed from command line without user interaction by passing the /SILENT flag. See all command line parameters that can be passed to the inno setup installer. See also Inno Setup website: http://www.jrsoftware.org/isinfo.php