Add the QUrl::FullyDecoded flag to the component formatting

Add the QUrl::FullyDecoded flag to the component formatting

This allows the QUrl component getters to return fully decoded data,
like they did in Qt 4. This is necessary for some use-cases where the
component like the user name, password or path are used outside the
context of a URL. In those contexts, the percent-encoded data makes no
sense, and the loss of data of what could be represented in a URL is
acceptable.

Also take the opportunity to expand the documentation of those getter
methods, explaining what the options argument does.

Discussed-on: http://lists.qt-project.org/pipermail/development/2012-May/003811.html
Change-Id: I89f743cde78c02f169c88314bff0768714341419
Reviewed-by: Lars Knoll <lars.knoll@nokia.com>
Reviewed-by: David Faure <faure@kde.org>
Reviewed-by: Shane Kearns <shane.kearns@accenture.com>