Bunch of stuff

COMMONS
- Moved ApplicPostesEventManager to commons and renamed
NetworkEventManager
- Added method isRunning() in NetworkReceiver for startThreads() and
stopThreads()

APPLICGARE
- Created 3 threads (NetworkReceivers) in ApplicGare as asked on p.16
- Created 3 handlers to go with those receivers
- Added a NetworkEventManager named eventManager (First step to move
event managing out of the frame)
- Deleted ApplicDepotReceiver as it was replaced
- Updated startThreads() and stopThreads()

APPLICPOSTES
- Added startThreads() and stopThreads() to keep the same logic

APPLICDEPOT
- Created a NetworkReceiver thread
- Created a handler to go with the receiver
- Added a NetworkEventManager named eventManager
- Deleted ApplicDepotReceiver as it was replaced
- Updated startThreads() and stopThreads()