Make nodeidx public.
Merge branch 'master' of github.com:0xdata/h2o-dev
Clear ONLY the bins field from frames, since that's the only one that Prithvi doesn't need for the summary view of a Frame.
Cleanup Vec.makeXXX calls

More javadoc
Loosen L_BFGS bounds, since it is a probabilistic algorithm
Fix broken refactor of training_frame for src
Expand MAX Value size before barfing, since tests for makeCon and
makeSeq can make max-sized Chunks of ints & doubles.
More Vec javadoc

Rollup stats, Key & Chunk management
Vec javadoc

Cleanup VectorGroup API slightly
Fix namespacing
More Vec javadoc examples
Make Vec types public for scala
mend RUnits. do not spec outputs in MRTask if none needed
Cleanup, javadoc Frame

Remove extra API calls, make a bunch private or package-private.  Start
to unify the various column & vec manipulators
Reorg Frame

Move accesors in one place up front, separate from Frame mungers (add &
remove & the bulk variants).
Cleanup a bunch of IdeaJ warnings, including javadoc cleanup.
One more classloader to search classpath.
Explicit DKV put on vectors before frame unlock.
Prefix generated key in DataFrame by useful name.
Updated Rollups to :
  1) prefetch results via DKV (instead of DTask ) to cache results locally(common use-case is to start rollups for multiple columns in parallel and later to fetch them via DKV, often sequentially).
  2) added support for multiple parallel rollups request - second request will wait for the first in-progress to finish, (previously unimpl)
  3) unified histogram with rollups to be retrieved/launched by the same mechanism, histogram being optional part of rolups

Also added test.
Added checksum computation to Rollups. Did not connect to public interface yet.
Changed DTask.dinvoke to call H2O.submit instead of directly compute2 to keep fj betavior (in particular, onExceptionalCompletion to be called)
Updated RollupStats task to do cleanup in case of exception.
Updated Rollups test.
Updated Frame task and glm task to reduce cost of transporting data info over network (removed adaptedFrame before sending over, not sending data info back at all, only one copy of data info in LineSearchTask).
Moved postWrite call in MRTask from postLocal to postGlobal (significant cost since it always fetches rollups of all vecs even if we did not change any of the vecs + if we did, we want to flip the mutating flag when all of mr task is done).