Log Message:
Update glib2 to 2.50.2

- grew a "gio" tool for the equivalent of ls, mv, mount, which also
  builds on Windows. "gio tree" is quite nice.
- updated to Unicode 9.0.0.
- added structured logging.

Full list of changes available at:
https://git.gnome.org/browse/glib/tree/NEWS?h=2.50.2