* SplitHTTP client: Add real upload / download splitting
* Transport: Add XHTTP as an alias of SplitHTTP
* XHTTP config: Use `downloadSettings` instead
* maxUploadSize -> scMaxEachPostBytes, default is 1MB on both sides (was 2MB on the server)
* minUploadIntervalMs -> scMinPostsIntervalMs, default is 30ms on the client (no server support for now)
* maxConcurrentUploads -> scMaxConcurrentPosts, default is 100 on both sides (was 200 on the server)
* maxUploadSize and maxConcurrentUploads can now be ranges on the client
* maxUploadSize is now enforced on the server
* the default of maxUploadSize is 2MB on the server, and 1MB on the client
* the default of maxConcurrentUploads is 200 on the server, and 100 on the client
* ranges on the server are treated as a single number. if server is configured as `"1-2"`, server will enforce `2`
* querystrings in `path` are now handled correctly