Add :title as attribute for basic_topic

When we update the <title> after editing a topic, we should use the raw
`topic.title` as `topic.fancy_title` may contains some htmlentities and
will be displayed as is in the browser tab.

This fix the following issue:

> Incorrect HTML title after editing title/category of topic
> http://meta.discourse.org/t/incorrect-html-title-after-editing-title-category-of-topic/8136
- like counts use number formatting (so 1100 is 1.1K like other counts)
- made 'likes' column wide enough to hold 3 digit and > 999 likes
Added discourse hub nickname operations simplify and avoid repeated code
Refactored username validations to avoid repeated code
404 if a category does not exist ....
custom title for user page
title for category pages
Merge pull request #1159 from jd-erreape/user_refactors

Refactors in user model
Merge pull request #1150 from mcwumbly/topic-likes

little tweaks to like counts in topic list view
Merge pull request #1148 from nterray/fix_html_entities_after_editing_topic_title

Add :title as attribute for basic_topic
better new user block PM copy
add "new" to PM title there for clarity
Added `In-Reply-To` and `References` email headers. Additionally removed username from
email replies and new posts to keep the subjects collapsable.
FIX: OpenGraph should feature the desired post, if found in the set.
Add blocked users count to dashboard
More nav links on admin users list page
Merge remote-tracking branch 'upstream/master'