Merge branch 'release-0.3.1'

* release-0.3.1:
  version bumpup
Merge branch 'release-0.3.2'

* release-0.3.2:
  version bumpup
  specs added
  async command execution
Merge branch 'release-0.4.0'

* release-0.4.0:
  version bumpup
  avoid crushes on event sending through configurator #516742
Merge branch 'release-0.4.1'

* release-0.4.1:
  version bumpup
  doc update
Codeclimate badge
added multipercentile sensor to the list of sensors
do not use real redis in specs, fix event sending cmd command
refactor drop method
refactor observe methods
refactor observe methods
refactor observe methods
refactor observe methods
remove the unused copy of a mysteriously duplicated method
widget refactoring
refactor zset-based timelined sensors
refactor timeline_within method
refactor reduce_all_raw method
move reduce methods to a separate module
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