Some code changes; some help still needed from Amy & Tomas
Tutorial and Vignette updates.
Merge branch 'master' of https://github.com/0xdata/h2o
Merge branch 'master' of https://github.com/0xdata/h2o
Revised per Amy's markup; please review changes to the following sections: 3.2, 3.3, 4, 5.1, 5.2, 5.3, 6, 7.1, 7.12
Merge branch 'master' of https://github.com/h2oai/h2o
Proofreading changes