Showing reply count in summary view
Minor: added missing spaces
Moved reply count next to annotation create time
Minor: changed date / reply order
Removed periods from the end of the fuzzy timestamps (consistently)
whitespace
remove obsolete Hypothesis.detail property

Use CSS to hide the reply count in the header for the detail view
and to do the slash delimiter.
consolidate more old stuff into app controller

- Don't track frame visible state in annotator service; do it in
  the app scope instead.
- Move the "back" logic into the controller
Merge branch '158_reply_count_in_summary_view' into develop