Move IEEE754 support code to lib/

It's not strictly core code.

Signed-off-by: Jens Axboe <axboe@kernel.dk>
diff --git a/iolog.h b/iolog.h
index a523d4d..53bb66c 100644
--- a/iolog.h
+++ b/iolog.h
@@ -1,7 +1,7 @@
 #ifndef FIO_IOLOG_H
 #define FIO_IOLOG_H
 
-#include "ieee754.h"
+#include "lib/ieee754.h"
 
 /*
  * Use for maintaining statistics