Includes clean up.

- Remove includes of config.h wrapped by HAVE_CONFIG_H. This
  is an obsolete vestige of our libvpx ancestry.
- Change (nearly) all remaining include sites; use proper path
  to the include relative to project root instead of ./.
- Correct include order where appropriate.
  - Note: This part of this patch is NOT exhaustive. In an
    attempt to be conseravative about the impact of this change
    I limited ordering and grouping changes to places that
    appear extremely unlikely to cause a problem. A more exhaustive
    follow up might be appropriate, but this issue can likely be
    handled organically from here on out.

Change-Id: I3b421ffd46c5da6ef78e43e7a6d3b9550cb30325
diff --git a/stats/aomstats.c b/stats/aomstats.c
index 0cfeea2..4a15adf 100644
--- a/stats/aomstats.c
+++ b/stats/aomstats.c
@@ -9,13 +9,13 @@
  * PATENTS file, you can obtain it at www.aomedia.org/license/patent.
  */
 
-#include "./aomstats.h"
+#include "stats/aomstats.h"
 
 #include <math.h>
 #include <stdlib.h>
 #include <string.h>
 
-#include "./tools_common.h"
+#include "common/tools_common.h"
 
 int stats_open_file(stats_io_t *stats, const char *fpf, int pass) {
   int res;