Another update

1. 1a0fff6 apps+model+utils: Implementing Interest/Data hop counting using new PacketTag by Alexander Afanasyev · 11 years ago
2. 400aae1 apps+utils: Correcting Interest-Delay tracing by Alexander Afanasyev · 11 years ago
3. edf24d9 Enabling trace sources for Interest-Data lifetimes by Alexander Afanasyev · 11 years ago
4. 1380010 zipf: Small changes (style and small logic correction) and adding documentation section by Alexander Afanasyev · 12 years ago
5. b0f8315 add zipf-mandelbrot support to NDN Interest app consumer by Shock · 12 years ago