Change log for kotlinx.coroutines

Version 0.5-beta

Switched to Kotlin version 1.1.0-beta-22 (republished version).
Removed currentCoroutineContext and related thread-locals without replacement. Explicitly pass coroutine context around if needed.
lazyDefer(context) {...} coroutine builder and LazyDeferred interface are introduced.
The default behaviour of all coroutine dispatchers is changed to always schedule execution of new coroutine for later in this thread or thread pool. Correspondingly, CoroutineDispatcher.isDispatchNeeded function has a default implementation that returns true.
NonCancellable context is introduced.
Performance optimizations for cancellable continuations (fewer objects created).
A guide on coroutines is added.

Switched to Kotlin version 1.1.0-beta-18 (republished version).
CoroutineDispatcher methods now have context parameter.
Introduced CancellableContinuation.isCancelled
Introduced EventLoop dispatcher and made it a default for runBlocking { ... }
Introduced CoroutineScope interface with isActive and context properties; standard coroutine builders include it as receiver for convenience.
Introduced Executor.toCoroutineDispatcher() extension.
Delay scheduler thread is not daemon anymore, but times out automatically.
Debugging facilities in newCoroutineContext can be explicitly disabled with -Dkotlinx.coroutines.debug=off.
xxx-test files are renamed to xxx-example for clarity.
Fixed NPE in Job implementation when starting coroutine with already cancelled parent job.
Support cancellation in kotlinx-coroutines-nio module