Check HTTP cache header to see if update is necessary, regardless of project stage. Set CSS content type to both SassResource and the wrapped Resource to ensure the underlying implementation would provide the correct behaviour for CSS files.
Correctly set Last-Modified HTTP header. Invalidate cache for browsers that do not check 304 status. Correctly compare If-Modified-Since header against lastModified time in seconds. Do not process resources that are already instances of SassResource.
0.3.3 release.