Add a StatCollector to measure tpt and delay for TCP.
Get rid of Werror; ns-2 is full of compiler warnings.
Replace c++0x with c++11
Move StatCollector into apps folder.
Add Exponential and Empirical Random variates for ON/OFF
Keith's ezio class for more pedantic atoi/atof.
Extend Application class to include a callback for ACKs
Exception class from ravinet/mahimahi
Mods to TcpAgent and RationalTcpAgent:
1. Better exception handling.
2. reset_to_iw() is now a C++ function.
3. new function advanceto().
4. Invoke app_->recv_ack() to process ack.
C++ rewrite of Hari's Tcl-based ON/OFF generator.
Use new C++ ON/OFF generator.
Must be a double to prevent overflow errors.
Reset to appropriate substream.
Use only non-zero flow_size. Unclear what to do if flow_size=0.
Use safer std::array instead of C array.
Asserts to ensure you don't reschedule a pending {start/stop}timer.
Rename start_timer_->on_timer_, stop_timer_->off_timer_
apps/onoffapp.{cc/h}: Modify ontype bytes to turn off once packets have been transmitted,
and not wait until they are all acked. This is to calibrate against Remy's rat-runner.

tcp.cc: The modified OnOffApp relies on the Application::resume() callback within ns-2,
called by TcpAgent::idle(). Unfortunately, idle() doesn't seem to be called ever,
as observed here: http://www.pollere.net/CoDel-ns-2.35.patch
I think this is an off-by-one bug, which this commit fixes. Hopefully it doesn't
have bad side effects.
Write to stderr to prevent interleaving.
Comment out the assert. I am not sure this is our problem.