Implement ability to report a pin

[martiangirlie]

User can report a pin for:

• An invalid picture
• The event not being there anymore

What will actually happen when someone reports a pin?

[martiangirlie]

Suggestions for reporting effects:

• A warning sign displays on the Pin
• after 'n' number of reports, the pin is removed

[martiangirlie]

Dependent on #55