Dropped open-method in gpgIO (replaced by open2)
Silence warnings from gpg2 when running under GNOME

gpg 2.0.23 outputs warnings about the GNOME keyring manager (without saying
anything at all about why it does it). The warnings aren't suppressed by
reducing verbosity, and it results in much less readable gpgpwd output.

This is done by redirecting stderr and discarding all data written to it.
It is only done when not in --verbose mode, and only when running GNOME (checks
XDG_CURRENT_DESKTOP) under X11 (checks DISPLAY).
Added a debug message when xclip is started