multitasking 1.1.0

Cooperative multitasking using asynchronous tasks, with support for forced task termination with `onExit` handlers.

1.1.0

• Fixed a bug that did not take into account that in Dart, a function cannot return a Future<Future<T>> result. Dart automatically flattens this value to Future<T>.
• Changed signature of the following methods in the Task class: Future<Task<T>> run(), Future<void> start() to Task<T> run(), void start(). First method (run) was changed because Dart blocks Future<Task<T>> Task<T>.run) until the task completes, the second method (start) was changed to be consistent with the first.

1.0.0

• Initial release