log: add Log::getLevelName()

include/villas/log.hpp

@@ -75,6 +75,7 @@ public:
 	void setLevel(const std::string &lvl);
 
 	Level getLevel() const;
+	std::string getLevelName() const;
 };
 
 } // namespace villas

lib/log.cpp

@@ -161,3 +161,8 @@ Log::Level Log::getLevel() const
 {
 	return level;
 }
+
+std::string Log::getLevelName() const
+{
+	return std::string(spdlog::level::to_c_str(level));
+}