catchup group: deselect everything before processing
enclose floating elements in public feeds

http://tt-rss.org/forum/viewtopic.php?f=10&t=2670&p=15780#p15780
Merge pull request #323 from levito/patch-6

enclose floating elements in public feeds
do not unpack all visible headlines in collapsed mode because those are unpacked on expand
Merge remote-tracking branch 'upstream/master'