Simplify ResourceTask creation
Fix indentation in URL loaders
Refactor resource loader protocol to send metadata first
Use rust-http typed headers
Extract content type and character set from HTTP response headers

We don't use this information anywhere, yet.
Add support for data: URLs

Fixes #778
make_url: Drop whitespace within data: URLs
Add a data: URL test page
Makefile: Consolidate lib crate rules
Run tests from non-main crates

Fixes #1035
Fix bitrotten tests
Comment out some failing tests for now

I'll open a ticket about these and make sure that they and/or the code under
test get fixed eventually.
Add tests for data: URLs
auto merge of #1037 : kmcallister/servo/data-url, r=jdm
Implement Document.createComment.
auto merge of #1036 : Ms2ger/servo/createComment, r=jdm