v0.9 of Ably's client libraries - simplifying channel lifecycle management

Ably's client libraries in version 0.8 were designed with the assumption that customers would handle channel failures themselves. However, many users did not expect channels to become detached and had not coded defensively for this situation. In response, version 0.9 introduces a new suspended state for channels when a connection becomes suspended or Ably cannot provide message continuity. Customers can listen for the suspended state events and implement their own business logic at this point. Automatic re-attachment of channels is also implemented in v0.9 to handle failure conditions, with client libraries attempting to re-attach detached channels every 15 seconds.