ui: use wstring in gui relates places

* loading icons
* loading fonts
* context menu action for copy path to clipboard
* context menu action for open containing folder

src/lib/utility/file/FilePath.cpp

@@ -381,6 +381,11 @@ std::string FilePath::getBackslashedString() const
 	return utility::replace(str(), "/", "\\");
 }
 
+std::wstring FilePath::getBackslashedWString() const
+{
+	return utility::replace(wstr(), L"/", L"\\");
+}
+
 std::wstring FilePath::fileName() const
 {
 	return m_path->filename().generic_wstring();

src/lib/utility/file/FilePath.h

@@ -51,6 +51,7 @@ public:
 	std::string str() const;
 	std::wstring wstr() const;
 	std::string getBackslashedString() const;
+	std::wstring getBackslashedWString() const;
 	std::wstring fileName() const;
 
 	std::wstring extension() const;