A new session is created every time you land on step1 page

[antoinefalisse]

See details here: https://github.com/stanfordnmbl/opencap-api-private/issues/97

[AlbertoCasasOrtiz]

Last Tuesday we discussed that it could be good if we solve this at session creation time.

When we create a session, we check if the last session was used.

• If it was used, we don't touch it and create a new session.
• if it was not used (e.g., there are no trials, not even calibration trial), we have two options:
  • Reuse it.
  • Remove it and create a new session (possibly simpler with the current implementation).

[suhlrich]

solved by #82