Merge branch 'release-0.4.1' into develop

* release-0.4.1:
  version bumpup
Merge branch 'master' into develop

* master:
  move reduce methods to a separate module
  refactor reduce_all_raw method
  refactor timeline_within method
  refactor zset-based timelined sensors
  widget refactoring
  remove the unused copy of a mysteriously duplicated method
  refactor observe methods
  refactor observe methods
  refactor observe methods
  refactor observe methods
  refactor drop method
  do not use real redis in specs, fix event sending cmd command
  added multipercentile sensor to the list of sensors
  Codeclimate badge
fix timepicker style