Calvin.48.preprocess

This branch includes:
 * preprocessing class (takes in a file, reads line, lemmatizes line, writes line, repeat)
 * Tokenizer from A1/A2 (with stanford-corenlp lib files)
 * tests for preprocessing (with test files for 1 line and 2 lines)
 * .gitignore set to ignore models.jar file (so place it in your actual lib directory after pulling)