src: clazy compiler warnings

get rid of most clazy warnings (https://github.com/KDE/clazy)
* range loop use refs
* qcolor ctor with ints
* missing Q_OBJECT macro
* use .constfirst instead of .first

enabled ccache for unix systems for fasterr recompiling
* if ccache is in path we use it now

src/lib_gui/qt/view/graphElements/QtGraphNodeData.h

@@ -8,6 +8,7 @@ class FilePath;
 class QtGraphNodeData
 	: public QtGraphNode
 {
+	Q_OBJECT
 public:
 	QtGraphNodeData(const Node* data, const std::string& name, bool hasParent, bool childVisible, bool hasQualifier);
 	virtual ~QtGraphNodeData();