Don't cachebust proxied files; they can still send an etag the browser will honor,  and the random querystring will break some sites.
Exposes Content-Type of server response of Datasource::data()
Proxy: 502 for invalid URLs.
Merge branch 'develop' of https://github.com/milimetric/limn into develop
Merge branch 'develop' of https://github.com/milimetric/limn into develop
Merge branch 'develop' of https://github.com/milimetric/limn into develop
Adds CORS support for datafile requests.
I think I accidentally made log scales default again, undoing that here