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
diff --git a/test/subtract_test.cc b/test/subtract_test.cc
index 498b6fa..a6ba557 100644
--- a/test/subtract_test.cc
+++ b/test/subtract_test.cc
@@ -17,10 +17,10 @@
 #include "test/register_state_check.h"
 #include "test/util.h"
 #if CONFIG_VP10
-#include "vp10/common/blockd.h"
+#include "av1/common/blockd.h"
 #endif
-#include "vpx_mem/vpx_mem.h"
-#include "vpx_ports/mem.h"
+#include "aom_mem/vpx_mem.h"
+#include "aom_ports/mem.h"
 
 #define USE_SPEED_TEST (0)
 
@@ -33,10 +33,10 @@
 
 class VP9SubtractBlockTest : public ::testing::TestWithParam<SubtractFunc> {
  public:
-  virtual void TearDown() { libvpx_test::ClearSystemState(); }
+  virtual void TearDown() { libaom_test::ClearSystemState(); }
 };
 
-using libvpx_test::ACMRandom;
+using libaom_test::ACMRandom;
 
 TEST_P(VP9SubtractBlockTest, SimpleSubtract) {
   ACMRandom rnd(ACMRandom::DeterministicSeed());