Release version 1.3.1

Support TimeLimiter in spring-cloud and added TimeLimiterConfigCustom…

…izer (resilience4j#840)

Updated release notes.

Updated RELEASE NOTES

Tests speedup (resilience4j#617)

* Tests speedup with reuse of spring context

* Few fixes for tests

* Speedup ratpack tests

* Configure retry in rxjava tests for speed up

* Configure retry in ratpack tests for speed up

* Configure timeout in rate limiter tests for speed up

* Configure timeouts in tests for speed up

* Some debug output clean up

* After merge fixes

Updated RELEASENOTES

Updated version to 0.16.0

Updated version to 0.15.0

Issue resilience4j#411: Fix Spring Boot AutoConfiguration

Issue resilience4j#288: Improve Kotlin support via Nullability annota…

…tions