add screen change detector for desktop share
remove blank space
Modify xcode project to fit common reorg.
Merge pull request #543 from zhilwang/reorgcommon-xcode

Modify xcode project to fit common reorg.
        use the same frame type EVideoFrameType in encoder internal
Remove unnecessary/superfluous parentheses in slice_multi_threading.cpp
Merge pull request #544 from ruil2/encoder_update

        use the same frame type EVideoFrameType in encoder internal
Merge pull request #542 from volvet/add-scene-change-detector-screen

Add scene change detector screen
Merge pull request #545 from mstorsjo/remove-extra-parentheses

Remove unnecessary/superfluous parentheses in slice_multi_threading.cpp