better consistency in `UrlAppend`/`UrlJoin`
minor tweaks For text encoding, using `.AppendTo` instead of `.Append` seems more consistent with other libraries.
better detection of nil output (for real this time)
better detection of nil output for decoding
shortcuts for introspection of response content type
add `Res.XmlWith`, `Res.XmlWithCatch`
add body cloning, add dumping
explicit utf-8 in content types
add CONNECT, TRACE, `(*Res).Err`
add `Cli`: alias for `http.Client` with "gr" compat