Allow start date to be null (simshaun#160)

Fix issue where first of january is skipped (simshaun#156)

* Fix issue where first of january is skipped

When using a BYSETPOS in a RRule the first of january is skipped because of a loose comparison.

* Prefer strict equality comparison

Add support for Hourly freq. on TextTransformer (simshaun#145)

* TextTransformer add support for Hourly freq - need test

* add test & translations

Merge pull request simshaun#125 from foaly-nr1/patch-more-immutable-t…

…ests

More test cases

fix bad phpdoc type (simshaun#149)

Replacing PSR-0 namespaces with PSR-4 (simshaun#124)

Add @throws to Rule constructor (simshaun#139)

Return class instance on setRDates and setExDates (simshaun#135)

CS update

Full support for immutables (simshaun#123)

* Run ArrayTransformerConstraintTest with using either \DateTime or \DateTimeImmutable

* Full support for immutables