* module/web/http.scm: Add commentary.
(parse-quality): Allow .NNN to be interpreted as 0.NNN.
* test-suite/tests/web-http.test ("request headers"): Add a test.
* module/web/http.scm (parse-media-type, validate-media-type,
(content-type): Change to represent media types as ("foo/bar" ("param"
. "val") ...) instead of ("foo" "bar" ("param" . "val") ...). Seems to
be more in line with what people expect.
* test-suite/tests/web-http.test ("entity headers"): Add content-type
test.
* test-suite/tests/web-response.test ("example-1"): Adapt expected
parse.
* module/web/http.scm: New module, declares known HTTP headers, and
their parsers and unparsers.
* test-suite/tests/web-http.test: Add test suite.
* module/Makefile.am:
* test-suite/Makefile.am: Adapt.
