Changes based on Ernesto's feedback:
* Add new init method too DDLogMessage which takes in a timestamp
* Make DDLog queueLogMessage:asynchronously: public
* Add nanoseconds to ASL capture timestamps
* Adjust some logging levels.
* TODO: Need to figure out how to get ddLogLevel into the ASLLogCapture module so it can be passed to the DDLogMessage init method. Perhaps declare it as extern in DDLog.h?