New feature : added an 'autoSave' option

[ptournet]

The option allows to automatically saving all modified files whenever a test run is started. For compatibility purposes, the default value is false, to keep the current behavior.

[leoblum]

+1. I also want to have this feature

[ptournet]

Hi @hbenl, I've modified my PR so there's no more merge conflict (there wasn't initially as far as I remember, though), can you consider merging it (as it's addressing a quite popular request) ? If you find things missing before you can, just let me know ! ;-)