version2_feature/copy experiment

- Adds backend functionality to copy an experiment and button to dashboard to call the backend
Description of feature: copying an experiment creates a copy the experiment object as well as the related the tracks, track weights, intervention points, and intervention point urls. 
@kyfantaz , the docs suggest there is perhaps an easier way to copy an instance by using the original object and setting it's primary key to null before saving.  That would save a little bit in terms of the create call with parameters vs. a save.  I'm also curious if you could get around looping through the related models by following the same referenced example which creates variable references to the original related collections, does a save, and then sets the collections directly on the saved model (resulting in additional saves).  Here's the link: https://docs.djangoproject.com/en/1.7/topics/db/queries/#copying-model-instances