ng-dateselect - add a way to disable certain dates

[lucienbertin]

right now, in the date-select picker, dates that are not between min and max are disabled. its good enough when you want to restrict in a define period, but when you want to restrict input in some more complex way its not possible

• disable week ends
• disable S23

needed in mealvoucher because there's a date-select that we want disabled days in between work contracts