In Atom feeds, prefer the ‘content’ item over the ’summary’ one
In Atom feeds, prefer the ‘content’ item over the ’summary’ one

Fix issue #570
ViennaRSS/vienna-rss,josh64x2/vienna-rss,ViennaRSS/vienna-rss,Eitot/vienna-rss,josh64x2/vienna-rss,ViennaRSS/vienna-rss,dak180/vienna,tothgy/vienna-rss,dak180/vienna,ViennaRSS/vienna-rss,dak180/vienna,ViennaRSS/vienna-rss,barijaona/vienna-rss,Eitot/vienna-rss,lapcat/vienna-rss,lapcat/vienna-rss,barijaona/vienna-rss,tothgy/vienna-rss,barijaona/vienna-rss,barijaona/vienna-rss,tothgy/vienna-rss,lapcat/vienna-rss,josh64x2/vienna-rss,lapcat/vienna-rss,barijaona/vienna-rss,Eitot/vienna-rss,Eitot/vienna-rss,josh64x2/vienna-rss,josh64x2/vienna-rss,dak180/vienna,tothgy/vienna-rss