Turn off Glib warnings and debug Glib critical logs

[jankammerath]

Partially described here: https://tecnocode.co.uk/2017/11/10/debugging-critical-warnings-from-glib-code/

The two errors that always come up and need fixing:

(iptvx:29955): Gdk-WARNING **: gdkwindow-x11.c:5573 drawable is not a native X11 window (iptvx:29955): GLib-CRITICAL **: g_array_free: assertion 'array' failed