Reimplement old differentiation between word polarity in WordMap
Subtract the inverted polarity when calculating freq
Populate negations statically
Merge pull request #8 from hlilje/reimplement-old-parser

Reimplement old parser
Add some neutral songs
Fix parser to read from subfolders and add placeholder file
Clarify variables
Fix bug when classifying words that are not in the corpus
Classify texts as unknown