Proper localization of AppController

xs/src/slic3r/IProgressIndicator.hpp

@@ -3,6 +3,7 @@
 
 #include <string>
 #include <functional>
+#include "Strings.hpp"
 
 namespace Slic3r {
 
@@ -42,13 +43,13 @@ public:
     }
 
     /// Message shown on the next status update.
-    virtual void message(const std::string&) = 0;
+    virtual void message(const string&) = 0;
 
     /// Title of the operaton.
-    virtual void title(const std::string&) = 0;
+    virtual void title(const string&) = 0;
 
     /// Formatted message for the next status update. Works just like sprinf.
-    virtual void message_fmt(const std::string& fmt, ...);
+    virtual void message_fmt(const string& fmt, ...);
 
     /// Set up a cancel callback for the operation if feasible.
     inline void on_cancel(CancelFn func) { cancelfunc_ = func; }
@@ -60,7 +61,7 @@ public:
     virtual void cancel() { cancelfunc_(); }
 
     /// Convinience function to call message and status update in one function.
-    void update(float st, const std::string& msg) {
+    void update(float st, const string& msg) {
         message(msg); state(st);
     }
 };