Don't expose filesystem list on /

Remove version from Makefile

Fix 404 errors after file ending change

Remove extra Sprintf call

Remove unused file

Use upload file extension when building name

Makes it easier to choose the correct program when viewing the files
that have been uploaded. For now we just take the extension from the
filename and lowercase it; in the future maybe it should be determined
from the file itself.

Don't expose local filesystem on invalid paths

Serve both download and upload from /

Add prefix to env vars

Initial implementation

Initial commit