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/project/Project.cpp

@@ -270,6 +270,7 @@ bool Project::requestIndex(bool forceRefresh, bool needsFullRefresh)
 	}
 
 	std::set<FilePath> filesToClean;
+	if (!needsFullRefresh)
 	{
 		std::set<FilePath> unchangedFilePaths;
 		std::set<FilePath> changedFilePaths;