refining test fixture a bit more, and adding simple test case for download with an error.
simplify the test fixture.
no point restricting TestHttpServer to ExternalResource api, since it's used via HttpTestFixture now.
Add basic directory listing using jsoup and test
Merge pull request #5 from rnc/BR4

Add basic directory listing using jsoup and test
Switch to passing String url into listing transport calls for consistency with other transport calls. Add more unit tests for HttpListing, and rearrange the resource directory structure (along with adjusting to changes I've made in the test fixture). Switch away from using TransferManagerImpl to drive the HttpListing tests.
don't depend on galley-core for unit tests, now that we're isolated to the local httpclient-based transport apis.