New features

• Issue #2921517: Wrong version is applied to the controller by bceyssens: Wrong version is applied to the controller
• Issue #2990684: Spelling fix by prashantgajare: Spelling fix

Fixed:

Adding basic functional test.

- Added period value object.
- Added concept of periods that can start before the given date; renamed getPeriod() to getPeriodFromDate(); added calculateStart() method.
- Added optional period label.
- Added support for entity types that represent periods, with conversion from a period object.

2.0 version will make use of the official CKEditor Mention plugin.

Issue #2994569 by nikunjkotecha, weseze: Provide UI for clearing the cache bins
Update readme for changes in this release and 1.3 release.