data: stop indexing of files with fatal errors and store them as incomplete (issue 358)

* avoid AST traversial for CXX translation units with fatal errors
* save all files within those translation units as incomplete
* show number of complete files in finished indexing dialog and overview stats
* display incomplete files hatched in graph view
* display incomplete file titles hatched in code view
* mention file incompleteness in tooltips
* removed derived Indexer classes and set ParserType via template parameter instead
* moved getSourceFileFromCDB from IndexerCxxCdb to IndexerCommandCxxCdb

bug id = 358

src/lib_gui/qt/element/QtCodeFile.h

@@ -47,6 +47,7 @@ public:
 	void updateContent();
 
 	void setWholeFile(bool isWholeFile, int refCount);
+	void setIsComplete(bool isComplete);
 
 	void setMinimized();
 	void setSnippets();