This fixes below bugs:

* pipe characters being counted as RTL character
* only first word being checked

* Use I18n.locale instead of ":en"
* Reset I18n.locale value after locale changing tests

* Add failing spec showing that human_locales does not match what i18n knows about

* Add missing `ar` key for arabic to human locales

* Remove duplicate `id` key from available locales

* Sort keys in human locales list

* Add spec for human_locale helper

The two methods `StreamEntriesHelper#stream_link_target` and
`StreamEntriesHelper#acct` are based on checking whether we are running
in an embedded view.

This adds some test helper code to make the testing easier. We extracted
some "magic strings" to constants to lower the coupling in the specs.

The code that generates CSS is based on a lot of boolean conditions.
The possible combinations of these grows exponentially as we add more
conditions.

Since most of the code is conditional on a single boolean, we tested the
following:

1. All `false`
2. All `true`
3. Each individual flag set to `true`

The methods tested are:

* `StreamEntriesHelper#style_classes`
* `StreamEntriesHelper#microformats_classes`
* `StreamEntriesHelper#microformats_h_class`

We used some random Arabic characters to test that the various RTL
conditions got triggered.

* Move site title helper to instance helper (name change only)

* Remove newline in <title> tag

* Add site_hostname helper method to wrap up local_domain value

* Use site_hostname helper in places that need local_domain value

* Add option to disable verify partial doubles

* Add show_landing_strip? helper method

* Use show_landing_strip? helper in accounts and stream entries views

* Fix naming in view specs

- Add some spec coverage for both methods
- Add explicit constant call-outs for where the params are from

* Remote spec for non-existent entry_classes helper method

This method no longer exists, and is handled by a local variable in a partial
instead.

* Remove spec for non-existent Account#ping! method

Removes:

- avatar_for_status_url
- relative_time
- reblogged_by_me_class
- favourited_by_me_class

This was used in the views/atom/user_stream.xml.ruby file, which no longer is
used.

* Replace will_paginate with kaminari

* Use #page instead of #paginate in controllers

* Replace will_paginate.page_gap with pagination.truncate in i18n

* Customize kaminari views to match prior styles

* Set kaminari options to match prior behavior

* Replace will_paginate with paginate in views

* Remove unused helper files

* Add coverage for application helper

* Add coverage for StreamEntriesHelper #display_name

* Add helper method to return Setting.site_title

* Use site_title helper in application layout

* Use site_title value for og:site_name

for avatars/headers, resize avatars down to 120x120 instead of 300x300. Set cache headers on S3 stuff, also
make it private (aka only accessible via expiring links to prevent hotlinking)

Fix #233, fix #268

registration API

as well as formatting of content

Added stack trace for SQL queries in development
Removed badly thought out accounts/lookup API

and atom feed generation to some extent, as well as the way mentions are
stored