Don't gzip already compressed fonts
Gzip files only if compression ratio high enough

Previously we would gzip if there was any size saving at all, however
shaving a few bytes of a multi-kilobytes file isn't worth the
decompression overhead.
Wrap Django exception with more helpful error message

If you reference non-existent files in your CSS then `collectstatic`
blows up in a way that suggests WhiteNoise is at fault. This makes the
error message a bit more friendly and informative.
New release