src: fixed some clang tidy warnings

* implemented CxxDeclName constructors that just move the members
* removed empty destructors because they disable default move constructors
* removed some unnecessary code
* replaced ".size() == 0" with ".empty()" because it's more explicit

src/lib/utility/file/FilePath.cpp

@@ -84,7 +84,7 @@ FilePath::~FilePath()
 
 boost::filesystem::path FilePath::getPath() const
 {
-	return boost::filesystem::path(*(m_path.get()));
+	return *(m_path.get());
 }
 
 bool FilePath::empty() const