QtDebug: Include file, line, function information

Record the file, line, and function where a qDebug, qWarning, qCritical
or qFatal call happens, and make this information available in a custom
message handler.

The patch uses the C preprocessor to replace qDebug, qWarning, ... with
a line that also records the current file, line, and function. Custom
message handlers can access this information via a new QMessageLogContext
argument.

Change-Id: I0a9b89c1d137e41775932d3b1a35da4ebf12d18d
Reviewed-by: David Faure <faure@kde.org>