fw+doc: Renaming and extending limit extenstion

SimpleLimits now called PerOutFaceLimits.  Also, there is now
PerFibLimits that is inherited from PerOutFaceLimits and implements
additional check.

Also, this commit includes a couple of tricks to improve documentation
of templated classes (PerOutFaceLimits and PerFibLimits). Not ideal, but
much better than before.
diff --git a/model/fw/green-yellow-red.h b/model/fw/green-yellow-red.h
index 363d0cb..371f7fd 100644
--- a/model/fw/green-yellow-red.h
+++ b/model/fw/green-yellow-red.h
@@ -34,7 +34,8 @@
     public Nacks
 {
 public:
-  static TypeId GetTypeId (void);
+  static TypeId
+  GetTypeId (void);
 
 protected:
   virtual void