MAHOUT-1597: A + 1.0 (element-wise scala operation) gives wrong result if rdd is missing rows, Spark side (dlyubimov)
This closes apache/mahout#33

Squashed commit of the following:

commit 9038b2c248ec163e0ff85dd37cb109345b3bbb9d
Author: Dmitriy Lyubimov <dlyubimov@apache.org>
Date:   Mon Jul 28 10:22:30 2014 -0700

    in-place performance enhancement at the risk of side-effects, for now

commit 35c873cceeda87b7b212677bffc0a21877932deb
Author: Dmitriy Lyubimov <dlyubimov@apache.org>
Date:   Tue Jul 22 15:34:00 2014 -0700

    CBind test tweak

commit 005aeccd353faeb59f2ddb2003f393a603978edb
Author: Dmitriy Lyubimov <dlyubimov@apache.org>
Date:   Tue Jul 22 15:33:18 2014 -0700

    Cbind test

commit 57f669a7d50097a5a816ce13ca8230f6c6742b65
Author: Dmitriy Lyubimov <dlyubimov@apache.org>
Date:   Tue Jul 22 14:57:57 2014 -0700

    Also fixing `A ew B` with missing rows operands

commit 2063c5ccaf88bf31d7f5c1dd3d1650925c4dfd58
Author: Dmitriy Lyubimov <dlyubimov@apache.org>
Date:   Tue Jul 22 14:12:56 2014 -0700

    style

commit 5d8e1407a7ea2535ae6d00701ed4f60390c1b30e
Author: Dmitriy Lyubimov <dlyubimov@apache.org>
Date:   Tue Jul 22 14:09:11 2014 -0700

    Orientation changing unary ops cannot produce missing rows

commit c9ac3be81ed464ccc4d440b8187e15efa9a21193
Author: Dmitriy Lyubimov <dlyubimov@apache.org>
Date:   Tue Jul 22 14:03:25 2014 -0700

    Tests, passing .

commit 1ff376b2ddd1bcbe61f896d14e27d7a413e7313c
Author: Dmitriy Lyubimov <dlyubimov@apache.org>
Date:   Tue Jul 22 13:23:14 2014 -0700

    Code up for lazy int-keyed missing rows fix

commit 746b3ddc6c0e7e8bb89ce591c32ba1b70ec688e6
Author: Dmitriy Lyubimov <dlyubimov@apache.org>
Date:   Tue Jul 22 11:25:57 2014 -0700

    WIP

commit 45642b65f3f1620a4e2187af4b2b54e26ce1c42e
Author: Dmitriy Lyubimov <dlyubimov@apache.org>
Date:   Mon Jul 21 18:19:37 2014 -0700

    WIP
closes apache/mahout#27, nonsensical PR
MAHOUT-1500: Implement H2O backend for Mahout Scala DSL

Barebone only, no logic yet. Compiles, tests fail with NotImplementedError

Signed-off-by: Anand Avati <avati@redhat.com>
MAHOUT-1500: Implement non-operator parts of H2O bindings

Signed-off-by: Anand Avati <avati@redhat.com>
MAHOUT-1500: Implement non Linear Algebra ops in H2O backend

i.e, mapBlock() and rowRange()

Provide dummy methods for all operators

Signed-off-by: Anand Avati <avati@redhat.com>
MAHOUT-1500: Implement Linear Algebra ops in H2O backend

- A'
- A'A
- A'B
- AB'
- A (element-wise) B
- A (element-wise) Scalar
- AinCoreB
- Ax
- Atx

All MathSuite tests are passing.

Signed-off-by: Anand Avati <avati@redhat.com>
MAHOUT-1500: Add String key support to DRM

Strings are stored in a Vec along with Frame in CheckpointedDrm

Signed-off-by: Anand Avati <avati@redhat.com>
MAHOUT-1500: Implement Par() operator

Signed-off-by: Anand Avati <avati@redhat.com>
MAHOUT-1500: Implement Cbind() operator

Signed-off-by: Anand Avati <avati@redhat.com>
MAHOUT-1500: use accessor methods instead of direct field access

Signed-off-by: Anand Avati <avati@redhat.com>
MAHOUT-1500: mahout h2o-node CLI for aux worker processes

Signed-off-by: Anand Avati <avati@redhat.com>
MAHOUT-1500: refactor frame_from_matrix() to reuse empty_frame()

Signed-off-by: Anand Avati <avati@redhat.com>
MAHOUT-1500: SequenceFile persistence (read/write) support

Signed-off-by: Anand Avati <avati@redhat.com>
MAHOUT-1500: Add tests for distributed operations

Mostly copy tests from sparkbindings with minor/trivial changes

Signed-off-by: Anand Avati <avati@redhat.com>
MAHOUT-1500: add README

Signed-off-by: Anand Avati <avati@redhat.com>
MAHOUT-1500: cleanup

- add code comments
- style fixes
- minor cleanups

Signed-off-by: Anand Avati <avati@redhat.com>
MAHOUT-1500: use the new test suites
MAHOUT-1500: make context public in CheckpointedDrmH2O

Signed-off-by: Anand Avati <avati@redhat.com>
MAHOUT-1500: Remove MathSuite from h2o/src/test

Signed-off-by: Anand Avati <avati@redhat.com>
MAHOUT-1500: ValueString API changes

Signed-off-by: Anand Avati <avati@redhat.com>