Overall code refactoring for NLP dependencies, chunks and feature extraction.
- Token dependencies are now represented as a graph (enhanced information).
- Chunks representation is now a list of chunks instead of just token features (enhanced information).
- Pre-processing features are now performed using a processing pipeline of the corpus.
- Removed previous dependency features using MALLET's pipeline.
- Defined FeatureType to support dynamic extraction of WORD, LEMMA, POS and CHUNK features.
- Added support to dependency features, between token and other tokens given a max hops limit.
- Added support to shortest path features, between token and closest concept.
- Added support to n-gram features for dependency windows and shortest path.