Fixed Nginx Vhost removal task.

Capistrano task wouldn't remove all the default Vhost files but it does now! Separated it into its own task.
Merge pull request #166 from tmcyf/fix-nginx-task

[WIP] Fixed Nginx Vhost removal task
Added missing commits from #166.

Fixed deploy example and updated production server IP.
Move iCal export to service. Closes #157.

Events should be exportable to iCalendar. This functionality is now extracted into a service.
Minor changes to ics_generator API (class method, naming)
Remove Ruby 2.1.0 from build matrix.

Something's up with this version on TravisCI's end.
Modify ics generator spec.