Moving Qt dependencies out of XMLInterface to XMLQtInterface.
Moved XML implementations deploying Qt stuff into subfolder.
[XmlCndInterface] readFile() interface change!

- readFile() put the read data into instance of ProjectData instead of a vector.
- For the same reason readConditions() was changed.
- The data is not added via the ProcessModel::addCondition() anymore!
Removed useless const specifier for return value.
Use call by reference to omit a copy.