This minimize code differences between AOM master and nextgenv2

Change-Id: If144865bdf3ef0818e7aac11018b9e786444c550

Cherry-Picked the following commits:
0defd8f2 Changed "WebM" to "AOMedia" & "webm" to "aomedia"
54e66767 Replace "VPx" by "AVx"
5082a369 Change "Vpx" to "Avx"
7df44f17 Replace "Vp9" w/ "Av1"
967f722f Remove kVp9CodecId
828f30ce Change "Vp8" to "AOM"
030b5ffc AUTHORS regenerated
2524caee Add ref-mv experimental flag
016762be Change copyright notice to AOMedia form
81e55269 Replace vp9 w/ av1
9b94565b Add missing files
fa8ca9f2 Change "vp9" to "av1"
ec838b76  Convert "vp8" to "aom"
80edfa01 Change "VP9" to "AV1"
d1a11fb9 Change "vp8" to "aom"
7b582513 Point to WebM test data
dd1a5c8d Replace "VP8" with "AOM"
ff00fc0f Change "VPX" to "AOM"
01dee0bb Change "vp10" to "av1" in source code
cebe6f0c Convert "vpx" to "aom"
17b05679 rename vp10*.mk to av1_*.mk
fe5f8a8a rename files vp10_* to av1_*

Change-Id: I6fc3d18eb11fc171e46140c836ad5339cf6c9419

script changed to remove extra entities and clang-format bot.

Change-Id: I102cd80fdf4b240e6e4d5172943e49146a601a72

Javan Whistling Duck release.

Change-Id: If44c9ca16a8188b68759325fbacc771365cb4af8

Change-Id: I9ffd30c88a5e40c555bde1f5efcf8a3c9ffcf5ff

- update .mailmap and AUTHORS
- update CHANGELOG

Change-Id: I3d75e8a6f87cabcbebc20e3ee5f3cd7db4d2e84d

Change-Id: Id9dd1802ae597a39eb46d2cbe531d5b04bd0a1c5

Change-Id: I5b0578f126308b4ec65d72553cc247b8e29c21a9

Change-Id: Ic7725e279d2263515e5312c152c58e1644eb2495

Change-Id: I784ea2b9fabbec1e99d02e97209981ff1b18ac82

Change-Id: I18e0a9e00731c23a2bdd1a978c8cb38f71e9029d

Change-Id: I0395ffa107651a773fd11d12682ab9372f76a90b

Change-Id: I1c6a275278788dfdc630ed436d2c770acfcbd097

A large collection of example files may be found at
 http://media.xiph.org/video/derf/
This also fixes a bug in ivfenc for uncompressed IVF input, which previously
 appeared not to skip past the file header the second time it opened the file.
I don't actually have an IVF file with which to test this fix, however.

Change-Id: Id69a1e11a3fa16c4a4fa8944e880bcea090cd52b