wip on the new selection mechnism

todo: cleanup code
todo: decide on behavior for fav and archive in search, they are no switches
todo: create archive and fav tags
todo: selected feed should be yellowish (gmail style)

done:
*all functionnalities are there
*new checkbox to select all feeds
*introduce draggable delay to be able to select quickly without triggering the drag event
*get more feeds when archive one feed to avoid not being able to scroll event if more feeds in db
*some js logic so checked feeds also appear checked in the search
fix bg color
many enhancements

latest: favorite/archive in search
update README
Merge branch 'selectAllFeeds'