PHP_CodeSniffer: Report warnings but return a zero exit code

I’ve committed this feature now. It’s only in the 2.x version because it changes the return value of the main printReport() method, which is a bit risky.

To use it, run PHPCS like this: phpcs --runtime-set ignore_warnings_on_exit true /path/to/code

Adding a comment because this issue came up in google before the wiki page. The option for this is now set using --config-set instead of --runtime-set as mentioned in this issue. The wiki has the correct commands listed, but it took me a bit to realize it was different:

Here are the current correct flags:

phpcs --config-set ignore_warnings_on_exit 1
phpcs --config-set ignore_errors_on_exit 1

Thats fine for errors, but I dont want it to happen with warnings

Another note to fellow search engine users – ignore_warnings_on_exit and ignore_errors_on_exit are only supported by phpcs, not phpcbf. (More specifically, the options are still parsed and result in Runner::run() returning 0, but Runner::runPHPCBF() ignores the return value of Runner::run() and instead returns exit codes based on the number of fixed/fixable errors in $this->reporter.)