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
antenna compression
Communication:
- added an option to request toa with simpy.event
- simulnet.ini[Network].communication_mode: 'synchro'/'autonomous'
if synchro : nodes get TOA regularly
if autonomous : nodes request TOA on visibles nodes
- TODO if autonomous : request TOA on localization request
Merge branch 'RT'
readd create_evt method for communication.TX()
resolved some bug after merge
resolved conflict
Merge branch 'master' of https://github.com/niamiot/pylayers into niamiot-master