Added rules to check if Xdebug is enabled or not

To fix #69 I just added two rules to check if **xdebug.default_enable** and **xdebug.remote_enable** are disabled.

There are more things that can be disabled, but, as they concern performance instead of security I did not add them, if it's ok I can add them, one example would be **xdebug.profiler_enable**.