Certify key.

In-place editing with a popup if user is allowed in app config file.
User must of course manage at least a private key. User identities of
target key may be selectively chosen. Optionally, certification may be
exportable and non-revocable.

nbproject/private/configurations.xml

@@ -13,6 +13,8 @@
         <gdb_interceptlist>
           <gdbinterceptoptions gdb_all="false" gdb_unhandled="true" gdb_unexpected="true"/>
         </gdb_interceptlist>
+        <gdb_signals>
+        </gdb_signals>
         <gdb_options>
           <DebugOptions>
           </DebugOptions>