JIRA: https://jira.springsource.org/browse/INT-4188
* add `<idle-event-interval>` XSD element
* add `FileTailingIdleEvent`
* move `TaskScheduler` and `getRequiredTaskScheduler` to `FileTailingMessageProducerSupport`
* add `setIdleEventInterval`
use taskExecutor instead of creating one
stop the scheduled task in case of `doStop()`
other required changes
update Test and Reference
implement changes required
What do you think about this checking if file exist before sending event.
Mock is used for `file.exist()` plus other minor updates
Polishing
* Some typos in the code as well as in the docs
* Fix `FileTailingMessageProducerTests.testIdleEvent()` to verify that `FileTailingIdleEvent` isn't emitted when file does not exist
f7b1ec8885