Hi Rouslan,
I went through your latest commits in your GSoC branch, see github for the small remarks.
You did a great job on creating the different classes (PMA_Header, PMA_Footer, PMA_Response, ...) moving functionality from other library files into it, and integrating these new classes in the current code base.
I think you've come to a point where these changes are ready to be merged with master. What do you think?