Memory Read and Write Pipeline

This commits starts jpeg encoding as soon as 8 lines are written into
image buffer.

Frame rate:
 - 100% encoding: Between 11 to 20 fps. Depends on image
 - 85% or 75% encoding: Between 20 to 30 fps. Highly depended on image
 - 50%: Close to 30. Almost independent of image.

Before starting the USB streaming reset must be pressed once otherwise
the output will be null.

This commit also heals issue Fix the timing constraints not met #68.