Unify logger configuration

[fblundun]

See #1367

The point of this is that it will be possible to configure the log level for both kinesis-s3 and the KCL by starting the application like this:

java -jar -Dorg.slf4j.simpleLogger.defaultLogLevel=debug kinesis-lzo-sink-0.x.0 --config myhocon

[alexanderdean]

Can we move the log level config into the hocon?

[fblundun]

Looks like you can configure it by changing the system property from inside the app:

val logLevel = config.getString("logLevel")
System.setProperty(org.slf4j.impl.SimpleLogger.DEFAULT_LOG_LEVEL_KEY, logLevel)

(from http://stackoverflow.com/questions/14544991/how-to-configure-slf4j-simple)