String changes in EOG

[Felix Riemann <friemann svn gnome org>]

Hi,

I just comitted a change to render several tooltip strings more precise
in EOG. 

Reference bug 511393:

-	  N_("Go to the previous image"),
+	  N_("Go to the previous image of the collection"),

-	  N_("Go to the next image"),
+	  N_("Go to the next image of the collection"),

-	  N_("Go to the first image"),
+	  N_("Go to the first image of the collection"),

-	  N_("Go to the last image"),
+	  N_("Go to the last image of the collection"),

Sorry for making this so short-term,

Felix