Support for + encoded space would be convenient in QUrlQuery::queryItem*()

I'm using QUrlQuery to parse HTTP URLs within an HTTP server and am facing the fact that when a web browser send data from an HTML form it always encode spaces as + instead of %20. And there are even no way to change that in the client side (apart from javascript) since even HTML 5 provides only binary or + encoding options.

I agree that + encoding is both odd and not compliant with URLs specification (RFC3986 and the like).
However, having a QUrl::HtmlFormEncoded in addition to QUrl::FullyEncoded in QUrl::ComponentFormattingOptions would enable a server to switch to this encoding when relevant.

I don't reopen QTBUG-10146 because I don't want support for default + encoding but for optionnal + decoding.

If someone agree with this proposal, I may even try to make a patch by myself if this is not viewed as a priority (in a general manner I don't think server-side is a priority for Qt and the current implementation - encoding spaces as %20 - is a good solution on the client-side).