Added datasets needed for new matrix multiply test.
added missing test data
Merge branch 'master' of https://github.com/h2oai/h2o
Proofreading changes
Updated github links
Updated links & PDFs
Updated matrix mul, added few R calls:
   1)removeVecs to let R drop frame columns without invoking slice operator (no copy, just remove the vecs from the frame and from KV)
    2)Order - get indexes of n smallest (largest) elements in the frame and output result as a new frame)
commented out sparse-multiply test
removed matrix test datasets.
Removed copies of test datasets.