Added model multiple file and folder upload.
Updated sidebar with images and data models.

Conflicts:
	app/db_api.py
	app/views.py
Step merge commit.

Conflicts:
	app/db_api.py
	app/views.py
More merge fixes.

Conflicts:
	app/db_api.py
	app/views.py
Update README
add migration version file
Merge branch 'khard/data_model' into bhard/data_model
change data model name constraint to views
Merge pull request #56 from ContinuumIO/bhard/data_model

Data model changes (v2)