UK|ME: added read only role to forms on sharing projects
UK|ME: only create project when project has not been created before
UK|ME: adding a form ensures users with project permissions have a read-only role to the new form, closes #442
UK: create a project if not created_by the user
Merge pull request #492 from onaio/442_readonly_role_to_forms_on_sharing_projects

read only role to forms on sharing projects and adding forms to projects
UK: add DigestAuthentication for the api endpoint, closes #286
UK: handle digest authentication failure only if it is a digest request