Add a pop-up at launch to let the user choose about the data tracking
Send user's activity data to the repository only if the user agreed to
Merge branches 'track-users' and 'track-users' of github.com:oster/PLM

Conflicts:
	doc/reporting/activity-report.org
document Matthieu's changes
improve the warning about PLM saving data remotly
Switch embeeded scala compiler to version 2.11.4
ask about saving when running the level, not as first interaction
allow to translate a new string
engine French translation back at 100%
adapt scala detection to 2.11