This patch introduces a goldentest.js. The tests inside
the file should rely on "golden" results rather then asserts.
For now, goldentest.js allows only image expectations. If the
actual result doesn't match the expected result, the two files
are created under `test/output` folder:
- The '-actual.png' contains the actual test result
- The '-diff.png' contains the diff between images
This patch:
- introduces StaticServer for the testing purposes
- switches tests from navigating to file:// to http://
- adds a test to cover Request.abort() functionality
References #1
