logic: preselecting SearchNodes for autocompletion by prefiltering the Graph with the entered Query

This change only shows matches in the autocompletion list that are prefiltered by the already entered query. The
autocompletion now also shows up after an operator of type . or > has been entered to show an alphabetical list of
possible tokens.

src/lib/data/graph/token_component/TokenComponentName.h

@@ -17,6 +17,8 @@ public:
 
 	virtual std::string getName() const = 0;
 	virtual std::string getFullName() const = 0;
+
+	virtual const SearchIndex::SearchNode* getSearchNode() const = 0;
 };
 
 
@@ -32,6 +34,8 @@ public:
 	virtual std::string getName() const;
 	virtual std::string getFullName() const;
 
+	virtual const SearchIndex::SearchNode* getSearchNode() const;
+
 private:
 	const SearchIndex::SearchNode* m_searchNode;
 };
@@ -49,6 +53,8 @@ public:
 	virtual std::string getName() const;
 	virtual std::string getFullName() const;
 
+	virtual const SearchIndex::SearchNode* getSearchNode() const;
+
 private:
 	const std::string m_fullName;
 };