add me function pointers for screen contents
enable Scroll detection into workflow
Fix QP<18 dequant UT bug at encoder side
This should be UT for QP<12.
Clarify a comment about MSVC parameters to fix building gtest

The temporary bug in gtest has now been fixed, but we still can keep
using the current way of fixing MSVC 2012 builds instead of switching
to the solution used previously.
Merge pull request #856 from mstorsjo/clarify-comment

Clarify a comment about MSVC parameters to fix building gtest
Merge pull request #831 from sijchen/md_merge144

[Encoder ME] Add ME function assignment for Screen Content Coding
Merge pull request #853 from dongzha/FixEncUTDequantBugMaster

Fix encoder dequant Unit Test bug for master
Merge pull request #844 from lyao2/scroll_detection

enable Scroll detection into workflow
Merge branch 'master' of https://github.com/cisco/openh264 into rc_doublefloat_fix
Merge branch 'rc_doublefloat_fix' of https://github.com/sijchen/openh264 into rc_doublefloat_fix