Fix special events in parking api

The scraperwiki service is either dead or at the very least flaky.
Hitting
https://views.scraperwiki.com/run/madison_parking_special_events_api/?
directly fails.

Swapped out use of scraperwiki with direct call to city parking-special
events page then used BeautifulSoup to parse html and derive expected
json.
Merge pull request #12 from chris-skud/master

Fix special events in parking api