Change mapreduce to calculate a similarity data

- also add a pcaServlet which consumes the similarity data and runs pca
on top of it. this will make a graph at a later point.
Add go fmt check to Travis config.
Simplify OAuth code by using common libraries

Part of #30 - this should work on windows now.
Merge pull request #29 from gkrasin/travis-gofmt

Add go fmt check to Travis config.