co-annotation analytics

[nlwashington]

from the old sim2 codebase, i took a crack at computing a co-annotation matrix using the term frequency-inverse document frequency algorithm (TF-IDF). that code is in these methods:

computeTFIDFMatrix getCoannotatedClassesForAttribute getCoAnnotatedClassesForIndividual getCoAnnotatedClassesForAttributes getCoAnnotatedClassesForMatches populateFullCoannotationMatrix getSubsetCoannotationMatrix initCoannotationMatrix

this needs to be ported from sim2 and refactored. it worked in my tests, but the performance was terrible once i scaled up to actual full-size data. i think the refactor will need to use a sparse matrix.

these will then provide the necessary calls for services to get commonly co-annotated classes