Bug fix, Task permissions(SSF)

Bug 1: http://demo.sahanafoundation.org/eden/pr/person/93/config
Bug 2: Duplicate doesn't work -- http://demo.sahanafoundation.org/eden/admin/user/1
Bug 3: I didn't handle the deleting of tasks when the task is open in SSF, my bad.
Also, allow authenticated users to create tasks in Sunflower.
Generally it is a bad habit to start variable names with an underscore without special reason.

Obviously "member_data" would be better than "_data", and "task_exists" better than "_record".

But this isn't a functional issue, just a coding style problem.