Migrates schema to many pictures per image.
Moves test data to import folder.
Adds missing indices to schema.
Fixes name of Picture model
Adjusts ExperimentParser to new concept of many pictures per image.
Reorganizes database.yml

Copy one of the examples into database.yml to configure database.
Fixes Picture model.

Adds missing attribute to the list of attrbutes allowed for mass assignment.
Adjusts seeds to new concept of pictures.