#234 Option to mark Weekends and public holidays

[Nishal Tellis]

Feature
Marking of Weekends and public holidays. Enable task not to take these days into consideration especially for repetitive tasks. Would also need an override for an individual task if necessary
Use
When scheduling tasks it should take this into consideration. For example: if a task is scheduled to repeat every 3 days. As the feature is not there now the task at times is scheduled to occur on a saturday or sunday at times which needs to be manually changed.