Fixes #100

Updated README with gear syntax to run the examples. Some of the examples (SequenceFileIO and KafkaWordCount) need README's or an update to this README because it's not clear how to run them. 
It seems that the "gearpump.streaming.executor.extraClasspath" of appliction is not handled? For example, in SequenceFileIO, the config is in AppMaster.AppDescription.Configs