this integrates advanced digitizing tools aka CAD tools in QGIS application and basically a port of CADinput plugin
* new class QgsMapToolAdvancedDigitizing shall be subsclassed if adv. digit. tools could be used in a map tool
* QgsAdvancedDigitizingDockWidget handles the interaction with the user and also perform the constraints (filters events)
* QgsAdvancedDigitizingCanvasItem paints construction lines on the canvas
- update methods of existing classes
- add comment to methods missing in the sip bindings
- split up collective sip files into single files and use
same directory structure in python/ as in src/
- add a lot of missing classes (some might not make sense because of
missing python methods in those classes)
- remove some non-existing methods from the header files
- add scripts/sipdiff
- replace some usages of std::vector and std::set with QVector/QSet
