* common base class QtGraphNode
* derived class QtGraphNodeData for nodes representing the data model
* removed GraphNode and GraphEdge interface classes
* moved and renamed files for DummyNode and DummyEdge
* refactored includes throughout Graph UI related files
* fixed crash when hovering GraphNode while expanding/collapsing it
* fixed clang warnings
* fixed GraphNodeExpandToggle to show empty circle
* fixed Searchbar showing empty block when nothing was parsed
* made template related edges in GraphView red
This change reduces the size of collapsed classes in the GraphView by removing the condensed view of the class access
nodes and using a single button next to the class name for collapsing and expanding instead.
Eberhard Graether