ENH: Connected Vector-image to Dataset PropertiesUpdated signal; Fixed bug in DatasetDescriptor::SetImageModelProperties(); Saved no-data fields updates in descriptor XML.

ENH: Specialized AbstractImageModel::BuildContext constructors; Changed ImageProperties inheritance (no mode a QObject); Added no-data flag & value fields to descriptor XML; Added modified flag to ImageProperties and linked it to VectorImageModel.

ENH: Updated version and data-version to 0.3.1 (in prevision of modifying CML descriptor format due to save of no-data properties).

BUG: Missing delete of bare pointer which in turns prevent dereferencing the current application (memory leak)

ENH: Adding result dir as a setting, enabling to set an arbitrary default directory to store results