Add toggling of transparency/video for the bottom filtered viewfinder

The video oceantrip-small.mp4 used in this application is a short clip
from http://www.youtube.com/watch?v=nzgfOBTNye0. The original video is
copyright of the "zero-project" (http://www.zero-project.gr/) and
licensed under the Creative Commons Attribution 3.0 Unported (CC BY 3.0)
license (http://creativecommons.org/licenses/by/3.0/).
Move AudioVideoCaptureDevice to App so no need to init it all the time
Add simple architecture diagram