Fix documentation

Migrate to Kotlin 1.3 coroutines, drop experimental from package

* Features based on version 0.30.0
* Uses Kotlin version 1.3.0-rc-57
* Uses Kotlin/Native version 0.9.2
* Uses AtomicFu 0.11.9-eap13
* Replace SuccessOrFailure with Result
* Replace buildSequence and buildIterator with sequence and iterator
* Apply @BuilderInference on all builders (including extension methods to workaround inference bug)

Version 0.30.0

Fix typo

Version 0.26.1

Migrate to Kotlin 1.3 coroutines, drop experimental from package

* Uses Kotlin version 1.3-M2
* Uses Kotlin/Native version 0.9

Version 0.26.0

Rename version 0.25.2 to 0.25.3 (for technical reasons)

Version 0.25.0

Version 0.24.0