Port folder renaming changes from AOM

Manually cherry-picked commits:
ceef058 libvpx->libaom part2
3d26d91 libvpx -> libaom
cfea7dd vp10/ -> av1/
3a8eff7 Fix a build issue for a test
bf4202e Rename vpx to aom

Change-Id: I1b0eb5a40796e3aaf41c58984b4229a439a597dc

build/make/rtcd.pl

diff --git a/build/make/rtcd.pl b/build/make/rtcd.pl
index 50093f4..59dbe52 100755
--- a/build/make/rtcd.pl
+++ b/build/make/rtcd.pl
@@ -250,7 +250,7 @@
   common_top;
   print <<EOF;
 #ifdef RTCD_C
-#include "vpx_ports/x86.h"
+#include "aom_ports/x86.h"
 static void setup_rtcd_internal(void)
 {
     int flags = x86_simd_caps();
@@ -285,7 +285,7 @@
 #include "vpx_config.h"
 
 #ifdef RTCD_C
-#include "vpx_ports/arm.h"
+#include "aom_ports/arm.h"
 static void setup_rtcd_internal(void)
 {
     int flags = arm_cpu_caps();