(#18) visibility: add a handler to work with visibility events
(#18) Cleanup, spec-tests for visibility handler
(#18) visibility handler: changelog
Merge branch 'feature/18-visibility-handler--rebase'

* feature/18-visibility-handler--rebase:
  (#18) visibility handler: changelog
  (#18) Cleanup, spec-tests for visibility handler
  (#18) visibility: add a handler to work with visibility events