Mobility :
- remove unecessary file from transit
- rename Person3 => Person
- add node_destiantion ini file ( now nodes room choice can be driven
  with an ini file and not only by a random process)

Simul:
- Move from SimPy.Simulation to SimPy.SimulationRT
- consequently : added a speed ratio option in simulnet.ini
Save is now an independent process.
Simulation results are saved into a dictionnary into S.save.savemat
default simulnet.ini modif
fix bug when using multiple rat
Save :
Correct bug of incorrect order of timestamps
add visibility parameter on each edges.
Todo : take into account for decide which node can be used for
localization
Merge pull request #81 from niamiot/RT

Clean up + save function