Changes to core classes needed for Word2Vec.
Word2Vec first pass.  Test data not committed due to size, but tests committed to show usage.  Tests will be rewritten for testing speed and smaller data.
Merge branch 'master' into brandon-word2vec
Merge branch 'master' into brandon-word2vec
add word2vec endpoints in R
add the endpoint name to constants in h2o-r
Moved word2vec from h2o-core to h2o-algos.
Merge branch 'brandon-word2vec' of https://github.com/0xdata/h2o-dev into brandon-word2vec
This didn't seem to be needed, but I'm adding it to keep parity with the other algos.
Added note on dataset location.
Set REST endpoint, and commented out code preventing compilation of R module.
Small tweaks with keys and locks.
Since putting all the result into ModelOutput floods JSON, this goes back to making the results into a frame pointed to by Model, and then putting accessor methods into Model as well.
Key clean up.
Temporarily disabled some assertions that require more than one column of input and require a response column.  The former doesn't work for word2vec, and the later shouldn't be enforced on unsupervised algos.
Made refactored names consisted.  Removed frame reference in favor of a Key only.  Set trainFrameSize. Fixes dropping of minWordFreq param.
Additional note on the current test dataset.
add polling to the R layer in w2vec
Cut negative sampling time by 2/3rds.
Small change to save on memory until the unigram table is converted into a function.