[impala] Move dashboards to own module
[impala] Add range facet
[impala] Fix facet toggling
[impala] Save dashboard
[core] New Document format
[impala] Save dashboard into new document model table
[core] Backport Django #16317 Self-referencing model with natural key

Getting error: dumpdata can't resolve dependencies
https://code.djangoproject.com/ticket/16317
[core] Set document natural keys as composite
[impala] Save or update a dashboard into a document
[oozie] Skeleton of new workflow editor

Can drag and drop a Pig action
[oozie] Create a new workflow
[oozie] Save a workflow
[oozie] List workflow editor page
[oozie] Generate XML workflow

Add Start and End nodes
Link new node to Start and End