Merge develop branch into master (#68)

* Fixing possible race condition when passing backoff around as a pointer.

* Adding a debug logger that is turned off by default.
Info logger is enabled by default but prints out less information.

* Removing OK Aurora acknowledgment.

* Making Mutex a pointer so that there's no chance it can accidentally be copied.

* Changing %v to %+v for composite structs. Removing a repetitive statement for the Aurora return code.

* Removing another superflous debug statement.

* Removing a leftover helper function from before we changed how we configured the client.

* Changing the logging paradigm to only require a single logger. All logging will be disabled by default. If debug is enabled, and a logger has not been set, the library will default to printing all logging (INFO and DEBUG) to the stdout.

* Minor changes to demonstrate how a logger can be used in conjunction to debug mode.

* Removing port override as it is not needed

* Changing code comments to reflect getting rid of port override.

* Adding port override back in.

* Bug fix: Logger was being set to NOOP despite no logger being provided when debug mode is turned on.

* Turn on logging by default.

* Removing option to override schema and ports for information found on Zookeeper.

* Turning off debug mode for tests because it's too verbose. Making sure LevelLogger is initialized correctly under all scenarios.

* Removing override fields for zk config.

* Remove space.

* Removing info that is now incorrect about zk options.

logger.go

@@ -33,6 +33,10 @@ type LevelLogger struct {
 	debug bool
 }
 
+func (l *LevelLogger) EnableDebug(enable bool) {
+	l.debug = enable
+}
+
 func (l LevelLogger) DebugPrintf(format string, a ...interface{}) {
 	if l.debug {
 		l.Print("[DEBUG] ")