Improvements for cleaner - integrational test, instant run

[plutasnyy]

Context of the issue/feature

Currently, development cleaner is very problematic. Our unit tests in java don't cover every scenario. I think that it would be great to have integrational tests for it. We can do this using fongo or Embedded MongoDB or maybe you know something better ;)

Second thing is that we can't run manually the cleaner in any other way than configure cron expression and wait. A button which starts cleaner's work could save a lot of time for developers.

[tkaik]

Cleaner integration tests done in https://github.com/Cognifide/aet/pull/489