add whatis entries to the POD

--- a/xs/UniqueApp.xs
+++ b/xs/UniqueApp.xs
@@ -54,6 +54,9 @@
 
 }
 
+=for object Gtk2::UniqueApp a single instance application
+
+=cut
 
 MODULE = Gtk2::UniqueApp  PACKAGE = Gtk2::UniqueApp  PREFIX = unique_app_
 
--- a/xs/UniqueBackend.xs
+++ b/xs/UniqueBackend.xs
@@ -16,6 +16,9 @@
 
 =cut
 
+=for object Gtk2::UniqueBackend IPC backend used by libunique
+
+=cut
 
 =for apidoc
 
--- a/xs/Unique.xs
+++ b/xs/Unique.xs
@@ -7,6 +7,10 @@
 
 MODULE = Gtk2::Unique  PACKAGE = Gtk2::Unique  PREFIX = unique_
 
+=for object Gtk2::Unique Use single instance applications
+
+=cut
+
 PROTOTYPES: DISABLE
 
 
