Merge pull request #21 from phenoscape/master

Convert project to Maven build.
Added class CommaAsAndAnnotator for CommaAsAndAnnotation module
moved code to CommaAsAndAnnotator class.
added comments
moved code related to LearnSeedNouns module to a new class named SeedNounsLearner. Added comments and added the module to the learner.
add one line
renamed MarkupByPOS to POSBasedAnnotator
Moved code of markupIgnore() to class IgnorePatternAnnotator
Moved doItMarkup() and doIt() and related methods into LearnerUtility class
moved code of adjective subject bootstrapping into class AdjectiveSubjectBootstrappingLearner
moved checkedWordSet from Learner class to DataHolder class
Created a module CoreBootstrappingLearner. Moved discover() methods and all other related methods into it.
Created a module of AdditionalBootstrappingLearner. Moved related methods into it
added module AdjectiveVerifier. Moved related methods into it
Moved method finalizeIgnored to class IgnoredFinalizer
Moved variable defaultGeneralTag from class Learner to Configuration
Moved code of tagging remaining isnull(tag) sentences to class NullSentenceTagger
fixed a bug in NullSentenceTagger
put code of commonSubstructure into a class CommonSubstructureAnnotator
moved test cases of CommonSubstructure to CommonSubstructureAnnotator