VFS Regression and Accuracy Fixes (#776)

* Regression and Mode Fixes

* Review Fixes

* string_view correction

* Add operator& for FileSys::Mode

* Return std::string from SanitizePath

* Farming Simulator Fix

* Use != With mode operator&

src/common/file_util.h

@@ -178,6 +178,9 @@ std::vector<T> SliceVector(const std::vector<T>& vector, size_t first, size_t la
     return std::vector<T>(vector.begin() + first, vector.begin() + first + last);
 }
 
+// Removes trailing slash, makes all '\\' into '/', and removes duplicate '/'.
+std::string SanitizePath(std::string_view path);
+
 // simple wrapper for cstdlib file functions to
 // hopefully will make error checking easier
 // and make forgetting an fclose() harder