GUACAMOLE-517: Add definition for "Print Screen" key to base RDP keymap.
GUACAMOLE-517: Add definition for "Print Screen" key to base RDP keymap.

mike-jumper/incubator-guacamole-server,glyptodon/guacamole-server,glyptodon/guacamole-server,mike-jumper/incubator-guacamole-server,mike-jumper/incubator-guacamole-server,apache/guacamole-server,glyptodon/guacamole-server,apache/guacamole-server,apache/guacamole-server,mike-jumper/incubator-guacamole-server