Squashed commit of the following:

commit 619b349786a32c46dc52b9da4ab9d13ce98660e7
Merge: 3e906ba 2e137a9
Author: Nick Holub <nikholub@gmail.com>
Date:   Wed Dec 4 18:21:05 2013 -0800

    Merge branch 'master' of https://github.com/DataTorrent/Malhar into dag_pull

commit 3e906ba38827cf1e61da0c5ad007411210be4d5b
Author: Nick Holub <nikholub@gmail.com>
Date:   Wed Dec 4 18:06:40 2013 -0800

    fix #369 Logical DAG - Legend

commit bddbba4f7b9fe54a5ef6f7290d514e0f1e421ef6
Author: Nick Holub <nikholub@gmail.com>
Date:   Wed Dec 4 18:03:10 2013 -0800

    fix #369 Logical DAG - Legend
Merge pull request #371 from nickholub/dag_legend_pull

Logical DAG Legend