Improved const-correctness.

Jupiter/Database.cpp

@@ -35,13 +35,13 @@ void Jupiter::Database::create_header(FILE *)
 {
 }
 
-bool Jupiter::Database::process_file(Jupiter::ReadableString &file)
+bool Jupiter::Database::process_file(const Jupiter::ReadableString &file)
 {
 	Jupiter::Database::data_->file_name = file;
 	return Jupiter::Database::Data::process_file(this);
 }
 
-bool Jupiter::Database::process_file(Jupiter::CStringType &file)
+bool Jupiter::Database::process_file(const Jupiter::CStringType &file)
 {
 	Jupiter::Database::data_->file_name = file;
 	return Jupiter::Database::Data::process_file(this);

Jupiter/Database.h

@@ -66,8 +66,8 @@ namespace Jupiter
 		* @param file File being processed
 		* @return True on success, false otherwise
 		*/
-		bool process_file(Jupiter::ReadableString &file);
-		bool process_file(Jupiter::CStringType &file);
+		bool process_file(const Jupiter::ReadableString &file);
+		bool process_file(const Jupiter::CStringType &file);
 		bool process_file(const char *file);
 		bool process_file(FILE *file);