Do not print ANSI color sequences on Windows

The Windows console doesn't support ANSI color sequences, so we don't
print then. Messages will just be without color.

Author: joto

src/logging.hpp

@@ -80,7 +80,12 @@ class logger
     bool m_log_sql = false;
     bool m_log_sql_data = false;
     bool m_show_progress = true;
+
+#ifdef _WIN32
+    bool m_use_color = false;
+#else
     bool m_use_color = osmium::util::isatty(2);
+#endif
 
 }; // class logger