Fixed a spelling error.
Added an explicit check for null configurations in the ApnsConnection constructor.
Let us never speak of this again.
Reworded docs for clarity.
Merge branch 'close_connections_when_inactive' of github.com:relayrides/pushy into graceful_shutdown_timeout

Conflicts:
	src/main/java/com/relayrides/pushy/apns/ApnsConnection.java
	src/main/java/com/relayrides/pushy/apns/ApnsConnectionConfiguration.java