Calendar function in the projeqtor

Holidays and other off days sould not be defined through calendars (forget about how MS-Projects does it !)
Calendars should define only "generic" off days (off days for every one)
If you have different off days (for instance for people working on different countries) you may define new calendars, but not one per resource.

To enter hlidays :
- define Administrative project
- add one or more activities on this project (holidays, sickness, ...)
Then, resources will enter real work in the future on this projet.