change #include "log.h" to <helper/log.h>

Changes from the flat namespace to heirarchical one.  Instead of writing:

	#include "log.h"

the following form should be used.

	#include <helper/log.h>

The exception is from .c files in the same directory.

src/target/testee.c

@@ -22,7 +22,7 @@
 #endif
 #include "target.h"
 #include "target_type.h"
-#include "log.h"
+#include <helper/log.h>
 #include "../hello.h"
 
 static const struct command_registration testee_command_handlers[] = {