Wording for scenario and transaction

[kevin-delmas]

The wording used in the code is confusing.
The notion of transaction, atomic transaction and multi-transaction should be preferred over the transaction/scenario wording that is not adatpted.
Considering a full refactoring to only use transaction and multi-transaction

[kevin-delmas]

@cpagetti @FredBoniol what do you think of such a refactoring?
Note that, we can do it in two different ways:

• either we just add the new names and leave the old ones accessible but deprecated
• or we remove the old ones, beware this will lead to a non retro-compatible version so all users that want to step to the new version need to update their models

[kevin-delmas]

So I propose to implement the refactoring in a dedicated branch. If the changes are satisfactory a new major revision (without retro-compatibility) will be pushed on Sonatype.

[kevin-delmas]

Fred is proposing to keep Scenarios but annote it as deprecated