tracers: New metrics in L3RateTracer

L3RateTracer now has 4 new per-face metrics:
- InSatisfiedInterests: a number of satisfied interests where face was
  part of the incoming set
- InTimedOutInterests: a number of timed out interests where face was
  part of the incoming set
- OutSatisfiedInterests: a number of satisfied interests where face was
  part of the outgoing set
- OutTimedOutInterests: a number of timed out interests where face was
  part of the outgoing set

Basically, for each face, sum of InSatisfied and InTimedOut (or sum of
OutSatisfied and OutTimedOut) equals to the number of totally received
(or forwarded) interests on the face.

Refs #1007 (http://redmine.named-data.net)