Committed a log level philosophy to writing. Still need to make reality match the philosophy, though.
Used variadic logging methods where possible.
Used the correct placeholders for SLF4J logging statements (oops).
Made logging statements stick to the philosophy in the README.
Evidently, static loggers are now The Official Recommendation.
Added slf4j-simple as a test dependency.
Added a missing <version> tag to the surefire configuration.
Awkward wording is awkward.
Fixed some placeholder goofs; embraced some more slf4j nuances to avoid explicitly checking the active logging level.
Fixed another placeholder goof.
Merge branch 'threadless_connections' into logging_normalization

Conflicts:
	src/main/java/com/relayrides/pushy/apns/ApnsConnection.java
Since all sequence number changes happen in the event loop, the sequence number can just be a plain old `int` instead of an `AtomicInteger`.
Moved a check inside an event loop `Runnable` for memory consistency.
Fixed a race condition where notifications could get lost if their write succeeded after the connection had handled a rejection, but before the connection had closed.
Clear the sent notification buffer after sending unprocessed notifications back to the listener.
Catch NullPointerExceptions and report them as a connection failure cause rather than checking for null and not reporting a cause.
Merge branch 'threadless_connections' of github.com:relayrides/pushy into connection_failure_listener
Merge branch 'threadless_connections' of github.com:relayrides/pushy into logging_normalization

Conflicts:
	src/main/java/com/relayrides/pushy/apns/ApnsConnection.java
Merge pull request #56 from relayrides/logging_normalization

Logging normalization
Merge pull request #51 from relayrides/connection_failure_listener

Connection failure listener (fixes #32)