v0.3.0

Release 0.3.0

• Performance improvements to Semaphore.

Breaking Changes

• Removes bound::[Channel|Sender|SenderRef]::unbounded_send
• Removes Semaphore::outstanding_permits and Semaphore::return_permits
• Alters the behaviour of bounded::Channel::from_iter to use the maximum of the iterator's length and the given capacity as the channel's capacity.