[rinekri]

Bugfix release.

• Fix NullPointerException on JVM/Android when launch/launchLatest/launchIfIdle/start/startIfIdle get a null argument; relaunch now re-runs with a null argument.
• Fix memory retention: the argument now lives in the JobHandle, and taskJobState keeps only the last finished job of each task (cancelled jobs are removed).
• Fix a dropped job and a permanent hang in start() when an observer of the task starts the next job from its collector.
• Version 2.0.1, CHANGELOG and README updated.