Update change log for upcoming 2.7 and 2.8beta release
Update change log for upcoming 2.7 and 2.8beta release

UweTrottmann/SeriesGuide,epiphany27/SeriesGuide,r00t-user/SeriesGuide,hoanganhx86/SeriesGuide,UweTrottmann/SeriesGuide,0359xiaodong/SeriesGuide,artemnikitin/SeriesGuide