Delete code relating to featureupdates experiment.

Change-Id: If218762c658bb8cbb3007cf2069123b3e05adcbc

Now this experiment has been merged.

Change-Id: I6c93784df89434c52a4eb8f977cd3745e269abf9

* changes:
  ssim: remove unused function dssim().
  detokenize: make local symbols static.

Merge "bitstream: give exported symbols a vp9_ prefix; make local symbols static." into experimental

* changes:
  tokenize: make local symbols static; give exported symbols a vp9_ prefix.
  encodemb: make locally used functions static.

Change-Id: Ie8ba934a757acec1c80ac37ab9307c9a2783254e

Change-Id: I2f1781c70b14bf1d7b6da75d1501718445552af0

Change-Id: Ia30924dc095663b04794902522308d822c1a5ad0

Change-Id: I77bc38b53428ff3e6456b5bc3516418892a58c1e

This is the condition under which it is called in onyx_if.c. Also remove
the unused function print_mv_ref_cts().

Change-Id: I51ea3720d46f86d136e2215e01cf9d6c7dfc41ea

Change-Id: I5898f64da77e43a3860a77f3bc49d64b725c278c

Change-Id: Ie80d13ce095faa8bca21bcdca3ca8249d9abc398

Change-Id: Iee0f707abbfe427b10058f6cf3be21b89d6a6e65

Change-Id: I3aa5b515c1eae19ae40ba9808d133590c95f7d13

Also include the correct header in ratectrl.c so it picks up these
function prototypes.

Change-Id: Ic51b13119f1625f0691917f2713b23d0249dece7

This way, the code is not compiled in by default, thus decreasing
overall binary size.

Change-Id: I85cac8f5a22a51a7d99c820ef6d6ed179d4106a0

Change-Id: Id55f3cd3c2f5857dbfd78703452740dfd63cdf41

Change-Id: I23aa5547b1e74f31327258dda0e330aae7ca1d35

Change-Id: I8341a19cb4f2234841a40fcbf560315f079b0108

Change-Id: Ica08c2c9cda9623389dde3f276dfed77c36e3a11

Also remove them from the header file.

Change-Id: I38182f70268fd47985fb1d8d87cdeb207f67e475

Change-Id: Id33c448084ca5c1c0525a05c3c4f35d6b0805fbe