Restore quality values as an intermediate step

In order to allow quality values to be pre-parsed and concatenated, the
Quality API is re-exposed as parseQuality and match/mapQuality. Quality
is still an opaque type.
Update username and copyright in Cabal file

The Cabal file information on URLs and licensing was out of date, and
has been updated. The gitignore has also been updated to include Cabal
sandbox files.
Merge branch 'master' of https://github.com/zmthy/http-media into language