use the second if with NGINX_SET_X_FORWARDED_HEADERS

introduce new variable NGINX_REDIRECT_TO_HTTPS for redirect

simplify the logic

fixed the typo

change the if statement logic

nginx error fix

apply the last fixed to all the required templates

Auto confirm for gcc/g++ ppa

`sandbox.sh` hang at the step when it add the gcc/g++ ppa for user respone(yes/enter), you make it better to make it auto install without user interaction. Thanks

fix the shell if syntax

fix the shell if syntax

Revert "Auto confirm for gcc/g++ ppa"