minor improvements and docuemntation

serviceinterface/ServiceInterfacePrinter.h

@@ -14,7 +14,13 @@ enum class PrintLevel {
 void setPrintLevel(PrintLevel printLevel);
 PrintLevel getPrintLevel();
 
-
+/**
+ * These functions can be used like the C stdio printf and forward the
+ * supplied formatted string arguments to a printf function.
+ * They prepend the string with a color (if enabled), a log preamble and
+ * a timestamp.
+ * @param fmt Formatted string
+ */
 void printInfo(const char *fmt, ...);
 void printWarning(const char* fmt, ...);
 void printDebug(const char* fmt, ...);