Create a custom time_tag_with_title helper, based on the rails 4 version of time_tag.
Use time_tag_with_title wherever time_ago_in_words is used.
Convert the thread decorator method to return a date object, and use that date with the time_ago_with_title helper.

Previously the string returned by the helper was un-translatable in any case.
Slightly nicer date formats.
Ensure the three divs (plus padding) is equal to the width of the container.

Previously we were getting reflows and a slight narrowing of each div due to
the table-cell handling.
Break long links in the group page actions. Fixes #300
Join message fragments with a newline.

This preserves a newline between quotes and replies underneath. An
explicit test is added and existing tests updated.

Fixes #247.
Update changelog.
Merge branch 'staging'