Removed default event value from being set to '1'

This behavior is different between the back-end tracking integration and the front-end: https://github.com/segmentio/analytics.js/blob/master/lib/integrations/google-analytics.js#L117

I personally prefer it not to default to anything, because it screws up our value tracking on events that don't have a dollar value, but either way the two libraries should remain consistent.
webhooks: increasing retries

Retrying for occasional webhook hiccups
Add support for USERcycle.
usercycle: adding extra docs and initial cleanup
Merge remote-tracking branch 'mattsjohnston/patch-1'
release: 0.1.5

  9eaad4f  webhooks: increasing retry count (calvinfo)
  7055390  usercycle: adding support for usercycle (lfittl)
  ded1f94  google-analytics: removing default value set to '1' (mattsjohnston)