Should use path relative to the application root when saving and loading files

[Connor Carney]

When scatterand saves, it uses the entire request path to determine the server root, which breaks saving and loading when the application is not deployed at the server root.

Example:
Scatterand is deployed at http://example.com/scatterand/, with a document prefix of /var/scatterand/documents
Request http://example.com/scatterand/document.schd
Filestore should load documents from /var/scatterand/documents/document.schd, but instead it looks in /var/scatterand/documents/scatterand/document.schd

[Connor Carney (cscarney)]

On inspection, this seems to be a bug when the server doesn't set the PATH_INFO environment variable correctly. There's not much that we can do about that from this end.