Integrating DUMPI's MPI trace replay with model-net. Currently, supports replaying MPI point-to-point messaging on top of torus/dragonfly and simple-net network models.

- "modelnet" parameter in cfg is now a no-op
- "modelnet_order" parameter in cfg is required,
  listing order in which networks are indexed to
  the model
- modified "model_net_set_params" signature
- updated tests to use the new interface

Updates to modelnet (1) Updated the mapping configuration for dragonfly (the mapping now distributes the routers equally on all the PES.  The old dragonly mapping configuration was placing the routers on a single PE which was causing congestion on that PE leading to slow model performance in parallel ) (2) Updated 'make check' to handle dragonfly and torus test cases as well (3) Remove the num_servers argument from model-net test case, the number of servers are now calculated from the config file (4) Placing the ross mapping parameters in the codes mapping file

Adding the torus network plugin with modelnet API, see model-net/README_MN_TEST.txt for instructions to run the test

Updates to model-net test program based on the new config file format. We can now configure all network parameters from the config file