NOTE: no models implement it yet

Build system and documentation files were largely hand-merged.

(i) more text on how to run dragonfly with network traces (ii) some stat reporting fixes with dragonfly (iii) modifying config file error handling for dragonfly/torus (iv) modified dragonfly reverse handler for out of order packet handling, now it deletes the hash entry that it created in forward mode

Updating the network model documentation, added examples on how to run network models with dumpi traces, fixed comm time in MPI Sim layer

Torus model revision: adding bubble flow control for deadlock prevention and updated congestion control

Updating the documentation of dragonfly synthetic tests (to be used as a usecase for codes-viz work)

More updates to network models, recording router busy times in stats, using RC stack for reverse computation instead of copying back data to message