If tree imports successfully, add supporting file.

This copies the input text (whether an uploaded file or pasted into a
form field) to a new file in the supporting-files area for this study,
so that it can be reviewed, downloaded, and deleted from within the
curation app. Fixes #418.

NOTE that this is in addition to the saving of input data to peyotl's
scratch folders. The latter is for diagnostic purposes.
On Oct 6, 2014, at 4:09 AM, Mark T. Holder <notifications@github.com> wrote:
> This should probably be:
> 
> size = os.path.getsize(os.path.join(*path_list))
> to be on the safe side. What is here works as long as the standard lib shutil includes the line "import os". That will probably continue to be true, but I don't think there is a commitment to that in the shutil docs
> 
Ah, good to know. I assume I should make the same change in the supporting-files controller as well, yes?

https://github.com/OpenTreeOfLife/opentree/blob/70244c3f8a37da91a3249accf00ea089a60806be/curator/controllers/supporting_files.py#L20-L27

Now I don’t recall why shutils was here in the first place, as it seems we're using the `os` module normally.

  =jimA==