GitLab

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

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

- Use uint32 instead of int for sequence generation
- Send sequence in READY message
- Check that DFSS file has not been compromised
- Remove sequence from DFSS file
- Use more explicit output for client during signature