v0.1.3: Poller function, enhanced helper library and more

Highlights

• Scheduler can accepts a poller function which may block the running native thread, and will call it in every turn with the time to next event.
• New helper libraries: promises (away.promise), series (away.series), high resolution timer (away.hrt).
• Scheduler will trigger the "stop" watcher (scheduler.watchers.stop) while leaving from .run and .runforever, even in error.
• Away call current_thread will instantly resume the caller thread.
• set_target_thread_uniqueness_checker() and set_target_thread_uniqueness_checker() in debugger are deprecated.