#22 Access tasks from calendar

[Caleb Lampen]

I'd like to be able to see the details about a task from the calendar view. I see a couple ways to do this.

1. Be able to double click on a task in the calendar view to access its details.

2. A plus/minus icon next to each task which, when clicked, will expand the task within the calendar view to show its details.

[nodiscc]

See https://sourceforge.net/p/osmo-pim/feature-requests/44/ for another UI implementation