Based on the initial patch by Dāvis Mosāns, many thanks for that!
There where many things left to do though and the following should
be read by everyone who wants to port a plugin to KUrl:

Add -DQT_NO_URL_CAST_FROM_STRING to your project, otherwise you
are doomed to long debug sessions.

Always be explicit when constructing a QUrl out of a QString.
Think about what the QString represents. Most of the cases we only
care about absolute paths, potentially with a remote host and protocol.
In such a case, the QUrl::fromUserInput is the correct choice. If its
a local file, i.e. comes out of QDir, QFileInfo etc., always use
QUrl::fromLocalFile. Generally, if your plugin only works with local
files, use the latter. *Never* use the QUrl(QString) constructor,
except if you really want to concstruct a relative URL. A common
pitfall is e.g. QUrl(IndexedString(...)). Always prefer
IndexedString::toUrl() instead.

Note that there are, sadly, far too many places in our code base
which abuse QUrl for general "Path" handling. If possible, rewrite
your code to use KDevelop::Path in such a case. It's also much
simpler to port the KUrl to Path directly.

REVIEW: 120123