Add a command "why3 bench"
Add a subcommand "why3 session create <file...> -P <prover...>" that does the following :
- Creates a new session with all the files specified
- applies for each file the transformation "split_vc" in the session
- for each proof node generated by "split_vc" add a proof attempt for each specified prover
- save the session without calling any prover
Also add a command "why3 bench " that plays all proof nodes in a session that have not been attempted. As it is supposed to be called on large sessions, it should save the session every minute. This way one could interrupt a bench then resume it later.
The combination of the 2 commands can be used to generate sessions for batch of files and then gather statistics.