A function macro named E clashes with internal boost definitions.  Rearrange
the order of header inclusion so that affected boost headers are included
before monotone defines the macro.

Also, stop bundling boost/circular_buffer, which is available in current
versions of boost. From Fedora.

Index: src/sanity.hh
--- src/sanity.hh.orig
+++ src/sanity.hh
@@ -14,7 +14,7 @@
 #include <ostream>
 #include <cstdio>
 
-#include "boost/current_function.hpp"
+#include <boost/current_function.hpp>
 
 #include "numeric_vocab.hh"
 #include "origin_type.hh"