reorder headers

Reordering all the headers to the following structure:

header file:
local
c
cpp (including openbmc libraries)

source file:
source.hpp (if applicable)
local
c
cpp

Change-Id: Ia74a5c761a3029819366159de3cfd40c5e4c4a2c
Signed-off-by: Patrick Venture <venture@google.com>
diff --git a/routing_table.hpp b/routing_table.hpp
index c96013e..0768d8e 100644
--- a/routing_table.hpp
+++ b/routing_table.hpp
@@ -6,8 +6,8 @@
 
 #include <iostream>
 #include <list>
-#include <string>
 #include <map>
+#include <string>
 
 namespace phosphor
 {