Add Nak, Chalk, and Scallop dependencies
Add .gitignore
CLI argument parsing
Add 'empty' lib directory to make bin/gpp happy
Add 'exp' target to run classification experiments
Implement support for reading tweet sentiments from XML
Add language utils (postive/negative words, stopwords)

Copied and modified from github.com/utcompling/tshrdlu
Implement simple polarity baselines

One selects the majority class from the training data, and the other
uses a simple count of positive/negative words.
Support Liblinear solvers with bag-of-words features
Hacky scripts to find good C parameter
Implement beginning of extended featurizer
Use extended features for explore_params.sh
Add stemmed bag of words features
Add polarity features
Add Stanford tweet converter
Add emoticon tweet converter
Implement support for detailed output
Update nak to 1.1.2
Support --version argument