make reply-to link depending on screen-width

make reply-to link depending on screen-width

* on small/smartphone-screens show "reply to" link above the posting and
  an eventual "shared by" link in a second line.
* on middle/tablet-screens show "reply-to" and "shared-by" link in one
  line above the posting, divided by a dot.
* on large screens show reply-to-link next to the time/date-link when
  posting was posted.

the first to positions are better for users with thick fingers on
smartphones. (like me)

Change "in reply to" to "is reply to". Sounds better.