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/asciik.hh
--- src/asciik.hh.orig
+++ src/asciik.hh
@@ -11,8 +11,8 @@
 #define __ASCIIK_HH__
 
 #include <set>
-#include "vector.hh"
 #include "vocab.hh"
+#include "vector.hh"
 
 class asciik
 {