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/roster.cc
--- src/roster.cc.orig
+++ src/roster.cc
@@ -11,10 +11,10 @@
 #include "base.hh"
 #include <algorithm>
 #include <set>
-#include "vector.hh"
 #include <sstream>
 
 #include "basic_io.hh"
+#include "vector.hh"
 #include "cset.hh"
 #include "database.hh"
 #include "platform-wrapped.hh"