0.12: Kotlin 1.1.0 release and reactive utilities

• Switched to Kotlin version 1.1.0 release.
• Reworked and updated utilities for
  Reactive Streams,
  Rx 1.x, and
  Rx 2.x with library-specific
  coroutine builders, suspending functions, converters and iteration support.
• LinkedListChannel with unlimited buffer (offer always succeeds).
• onLock select clause and an optional owner parameter in all Mutex functions.
• selectUnbiased function.
• actor coroutine builder.
• Couple more examples for "Shared mutable state and concurrency" section and
  "Channels are fair" section with ping-pong table example
  in coroutines guide.