Make number of tries to fetch script-version tweakable (in-code for now)
Make number of tries to fetch script-version tweakable (in-code for now)

* Sometimes the github api-request fails, probably due to heavy traffic, so this
  just tries twice before borking
* If we ever decide it is worth making this tweakable by advanced users we can
  move the fetchTries assignment up to the settings section.

baatochan/GoogleContactsEventsNotifier,GioBonvi/GoogleContactsEventsNotifier,rowanthorpe/GoogleContactsEventsNotifier