gme: changed submodule source

source is now kode54's version again; Data_Reader put outside of the gme
git tree

Signed-off-by: Carlos Rafael Giani <dv@pseudoterminal.org>
gme: fixed leaks + added track length log details

Signed-off-by: Carlos Rafael Giani <dv@pseudoterminal.org>
updated README

Signed-off-by: Carlos Rafael Giani <dv@pseudoterminal.org>