ui/logic/data: show parse errors in CodeView

This change saves the errors while parsing in the Storage and displays them in the CodeView. The error messages can be
read in the tooltip on hovering. The error count is visible in the status bar.

src/lib/data/parser/ParserClient.h

@@ -49,6 +49,8 @@ public:
 	ParserClient();
 	virtual ~ParserClient();
 
+	virtual void onError(const ParseLocation& location, const std::string& message) = 0;
+
 	virtual Id onTypedefParsed(
 		const ParseLocation& location, const std::vector<std::string>& nameHierarchy,
 		const ParseTypeUsage& underlyingType, AccessType access) = 0;