Improved answer applience item in news-feed

In line with other items. Show question and answer's excerpt.

Also some new translations.
Large icons in news-feed.

Use plus instead of plus-circle icon in newsfeed.

New translations.

Minor layout changes.
Don't mention same item twice in news-feed

In newsfeed view component store every mentioned item (story, question or answer) and skip it next time.

Removed remove items from news-feed.
0.10.0