Use MP4Muxer from jcodec on API level 16-18 and streamable

MediaCodec and MediaExtractor is available from API level >= 16 in fact. But MediaMuxer is only available in API level >= 18.

Another problem is "The mp4 file will not be streamable." message printed. It is [bug or bad spec of MediaMuxer.cpp](http://stackoverflow.com/a/24046773/1474113).

[jcodec](https://github.com/jcodec/jcodec) does not depend on Android API, and also seems to support streaming.

NOTE:

Because compatibility test suite (CTS) for MediaCodec is [first added in Android 4.3 (API 18)](http://bigflake.com/mediacodec/).
So CTS test runner should be implemented for older devices.