Readd a missed prototype for the WelsProcessingSampleSad8x8_neon function

The common WelsSampleSad8x8_neon function has different alignment
requirements than WelsProcessingSampleSad8x8_neon - until it has
been sorted out that the common version can be used in the processing
lib, the separate version for processing is used.

This fixes building with neon optimizations enabled.
Merge pull request #578 from mstorsjo/fix-arm-build

Readd a missed prototype for the WelsProcessingSampleSad8x8_neon function
fix build failure without gtest
Add DecUT Motion Compensation on New Code Base
    add complexity calculation for screen content
Merge pull request #581 from licaiguo/fix-build-without-ut

fix build failure without gtest
Merge pull request #582 from ruil2/vp_complexity

    add complexity calculation for screen content
Merge pull request #583 from dongzha/MotionCompensation

Add DecUT Motion Compensation on New Code Base
Merge remote-tracking branch 'upstream/master' into travis.osx