Fix 'diagnose' command output and error

This fixes the output of the `diagnose` command:

* Adds newline after every JSON schema error/warning
* Hides suggestion for PHP 5.3.4 if not even 5.3.2 is available and error is already shown
* Shows INI message only once at the end.
* Fixes error `Missing argument for closure...` on line 260 (now 257)