Add class loading infrastructure.

Change-Id: I94bdabcefdf1030ee1827d9219eaf60e4dc818ca
diff --git a/src/logging.h b/src/logging.h
index ccab249..e1b99d6 100644
--- a/src/logging.h
+++ b/src/logging.h
@@ -74,6 +74,7 @@
 #endif
 
 #define LOG_INFO LogMessage(__FILE__, __LINE__)
+#define LOG_WARN LOG_INFO  // TODO
 #define LOG_FATAL LogMessageFatal(__FILE__, __LINE__)
 #define LOG(severity) LOG_ ## severity.stream()
 #define LG LOG(INFO)