gnome-keyring Review? Certificate request parsing and viewing

[Stef Walter <stefw collabora co uk>]

I've added certificate request (both PKCS#10 and SPKAC) parsing and
viewing to libgcr. That means files of these types will be viewable by
opening them.

The implementation is here:

https://bugzilla.gnome.org/show_bug.cgi?id=663604

Anyone interested in looking this over to make sure I didn't miss
something important?

Cheers,

Stef