File upload

Adding file upload page per study. This is ready for review but note that this is not final and will need to be modified to work. Things to do are: finalize how the visualizations should work with this page, set the upload file types for each group and decide what's erasable.

Note that `resumable-uploader.js` and `resumable-uploader.js` are 3rd party libraries but `resumable-uploader.js` needed (and perhaps will need) to be modify. At this point the only changes are in the first lines of `addFile` (lines 118-124).
Can you add a description of the returned value?