0.2.0

A couple of new methods added to Client.

• Client.getSubscription(channel: String) -> CentrifugeSubscription? to get Subscription from internal client registry
• Client.removeSubscription(_ sub: CentrifugeSubscription) to tell Client that Subscription should be removed from internal registry. Subscription will be automatically unsubscribed before removing.

See more details in the pull request #36. In short, subscription removing can be helpful if you work with lots of short-living subscriptions to different channels to prevent unlimited internal Subscription registry growth.