Implementing base support for TCP-style window-based limiting on per-FIB-prefix and per-face granularity

Currently, limits are supported only by ndn::fw::Limits forwarding
strategy and only at the very basic (not fully tested) level.
diff --git a/model/fw/ndn-forwarding-strategy.cc b/model/fw/ndn-forwarding-strategy.cc
index 1cbcd09..cf09878 100644
--- a/model/fw/ndn-forwarding-strategy.cc
+++ b/model/fw/ndn-forwarding-strategy.cc
@@ -427,8 +427,8 @@
 
 bool
 ForwardingStrategy::WillSendOutInterest (const Ptr<Face> &outgoingFace,
-                                             Ptr<InterestHeader> header,
-                                             Ptr<pit::Entry> pitEntry)
+                                         Ptr<InterestHeader> header,
+                                         Ptr<pit::Entry> pitEntry)
 {
   pit::Entry::out_iterator outgoing =
     pitEntry->GetOutgoing ().find (outgoingFace);
@@ -462,7 +462,7 @@
 }
 
 void
-ForwardingStrategy::WillErasePendingInterest (Ptr<pit::Entry> pitEntry)
+ForwardingStrategy::WillEraseTimedOutPendingInterest (Ptr<pit::Entry> pitEntry)
 {
   // do nothing for now. may be need to do some logging
 }