Modularize parser component

This build made some refactoring on the structure of the project so that Parser Component has a clearer API now. The other components can communicate with Parser Component by the ParserService Interface. The clients of Parser Component do not need to bother how to manipulate different parts of the parser to finish a task now, what the other components need to do is providing the input to appropriate port of the ParserService instance, and then the desired output will be returned. The clients who use Parser Service can put new requirements on Parser Component by adding methods in ParserService Interface. 
@owolabileg  @pdaian  @yzhang90 Please review.
 
the rest of these methods don't seem to have anything to do with parsing? Something feels like it's factored wrong here to me. It feels like you're just moving methods around and performing procedural transformations instead of thinking critically about the API you want to have and bringing the code in alignment with that API.