Various updates to vp8.

Change-Id: Icc7a816491897107764e4c936288e9000e6319b8
sse2 visual studio build fix

Change-Id: Id8c8c3be882bcd92afea3ccec6ebdf3f208d28ef
acm_random: provide full range for Rand16()

the gtest implementation used only returns values between 0 and 2^31-1

+ temporarily disable some tests in fdct8x8_test which misbehave with the
  new range

Change-Id: I45381076f0bea3317cc6728305890e4fd2f2facd
Merge "sse2 visual studio build fix"
Merge "acm_random: provide full range for Rand16()"
Merge "Various updates to vp8."