Tree clean up.

Relocate C source and include files from the root of the
repository to more appropriate places. Helps quiet linters.

- Move common app support sources and includes to common/
- Move apps to apps/
- Move stats support to stats/
- Drop unnecessary includes of aom_config.h where appropriate
- Clean up include order where appropriate
- Change CMake build to accomodate the above
- Fix resize_util and add it to app targets.

Change-Id: I268838e93400c67eb365aba9d2ecb2891538fc07

examples/lightfield_decoder.c

diff --git a/examples/lightfield_decoder.c b/examples/lightfield_decoder.c
index 0fb970b..b3e1637 100644
--- a/examples/lightfield_decoder.c
+++ b/examples/lightfield_decoder.c
@@ -29,10 +29,8 @@
 
 #include "aom/aom_decoder.h"
 #include "aom/aomdx.h"
-
-#include "../tools_common.h"
-#include "../video_reader.h"
-#include "./aom_config.h"
+#include "common/tools_common.h"
+#include "common/video_reader.h"
 
 static const char *exec_name;