Kotlin 1.3

This release is compiled with Kotlin 1.3.10 (and kotlinx.coroutines 1.0.1), which means it is now using stable coroutines. The Splitties artifacts have also been updated to version 2.0.0.

Changes

• Now uses stable coroutines.
• All the package names changed, dropping experimental from the hierarchy.
• The API is still experimental, and is annotated accordingly.