stop using unnecessary validators for signin

The only thing that matters is whether the username/password
combination is correct. There is no reason to enforce the length
requirements here.
validate the characters in usernames
upgrade horus and hem
compare usernames with dots ignored
Easy fix for 281
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)
make treatment of '.' in username cross-dialect
remove unused import
Merge pull request #282 from hypothesis/fix_for_281

Easy fix #281
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
Merge branch '271-feature-username-validation' into develop
remove bad validation merge
Merge branch 'develop' of https://github.com/hypothesis/h into develop