essimporter: Don't use "std::string" to store paths.

apps/essimporter/importer.cpp

@@ -85,7 +85,7 @@ namespace
 namespace ESSImport
 {
 
-    Importer::Importer(const std::string &essfile, const std::string &outfile, const std::string &encoding)
+    Importer::Importer(const std::filesystem::path &essfile, const std::filesystem::path &outfile, const std::string &encoding)
         : mEssFile(essfile)
         , mOutFile(outfile)
         , mEncoding(encoding)
@@ -112,7 +112,7 @@ namespace ESSImport
         std::vector<Record> mRecords;
     };
 
-    void read(const std::string& filename, File& file)
+    void read(const std::filesystem::path &filename, File& file)
     {
         ESM::ESMReader esm;
         esm.open(filename);

apps/essimporter/importer.hpp

@@ -1,7 +1,7 @@
 #ifndef OPENMW_ESSIMPORTER_IMPORTER_H
 #define OPENMW_ESSIMPORTER_IMPORTER_H
 
-#include <string>
+#include <filesystem>
 
 namespace ESSImport
 {
@@ -9,15 +9,15 @@ namespace ESSImport
     class Importer
     {
     public:
-        Importer(const std::string& essfile, const std::string& outfile, const std::string& encoding);
+        Importer(const std::filesystem::path &essfile, const std::filesystem::path &outfile, const std::string& encoding);
 
         void run();
 
         void compare();
 
     private:
-        std::string mEssFile;
-        std::string mOutFile;
+        std::filesystem::path mEssFile;
+        std::filesystem::path mOutFile;
         std::string mEncoding;
     };