Enable STRICT PHP error reporting by default

This is a development environment, y'know. It's useful to write errors to `/tmp/php_errors.log` so you can have a window open to see any PHP notices, etc.

One issue I've found: `/tmp/php_error.log` is created as root:root, which means it isn't writable by the webserver. Changing the access permissions fixes this. I think there's some other config declaration I'm missing but I haven't been able to track it down yet.