Add CMake build system, work with recent ffmpeg

Downloads and builds ffmpeg 1.1.2 and x264-snapshot-20130217-2245-stable
Replace img size recognition to mandatory setting

This is done to avoid taking information from corrupted images.
Having mandatory settings, we can check images for comformance.
Customize log level
Propagate encoding error as app retcode
Improve output printing prioritization
Update README
Update scripts and config sample