This huge commit adds the following features:

- Change default timeout to 5 sec (to be updated soon)
- Don't send TTP information in contract file, but during start signal
- Platform: load and save TTP data from a local file
  New flags: --addr and --ttps
- Platform ttp command: automatically save ttp data in the local file
  (addr and certificate hash are the only values needed by the platform
  and the clients)
- Update integration tests to integrate TTP

- pAPI allow to send multiple IPs
- Rebuild of protobuf files with updated protoc
- Send client interface ips
- Remove user ip & port from mongo
- Fix uint port issue

- Add hash check to client connect()
- Update net.Connect calls
- Implement remote cert hash check

- Add sub-commands flags
- Factorize version commands
- Fix import format
- Fix GUI

- Factorizes code between promises and signatures
- Add a cooldown before starting the first round
- Add demonstrator trace in integration tests

Fix #3 - Should be merged asap in 192 branch

- Draw and place clients
- Draw arrows
- Draw servers
- Add icon