Some tiny fixes in Debugger

[rindeal]

No description provided.

[w00fz]

That strtolower was definitely meant for $mode but your fix is too strict, maybe:

$mode = strtolower($config->get('system.debugger.mode'));

So you can then just do $mode == 'production'.

[rindeal]

I wouldn't do those strtolower checks at all, if a user misconfigures his .yaml files then he might expect his configuration not to work. This hyper protectiveness only slows down the execution and Grav should be kept "Crazy Fast". The speed improvement in using === over == is described here, it's tiny but still something.

[rhukster]

I'll discuss with the team, but your changes is probably fine. We're definitely interested in any and all optimizations. Every little bit helps and if you find any other things, even if they are minor, please submit other pull requests. It's great having a fresh pair of eyes on it. thanks!