* Add language detection via WhatLanguage and (de)serialization of it through Atom

* Fix default language in ProcessFeedService

* Re-add newline before 'react-rails' Gem to fix groupings

Fixes Code Climate issue

as suggested, moving to view tests rather than a controller test
replaces https://github.com/tootsuite/mastodon/pull/1786 which i will
close momentary

This commit introduces Capybara and the first feature spec.

I focused on coverage for log in for the first feature spec because that would
have prevented 624a9a7136 causing #1236.

The pkg-config gem was necessary in order for nokogiri to find the system
libraries when building on OpenBSD.

Closes #1637

Signed-off-by: Bryce Chidester <bryce@cobryce.com>

* Add sprockets-rails to Gemfile

* Add sprockets-rails to Gemfile.lock

* Update show.html.haml

* Update index.html.haml

* Update admin.html.haml

* Update auth.html.haml

* Update embedded.html.haml

* Update public.html.haml

* 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

* Add exclude_types param to /api/v1/notifications

* Exclude notification types in web UI through exclude_types in the API

* Update rspec-rails to version 3.5.2

* Update addressable to version 2.5.1

* Update autoprefixer-rails to version 6.7.7.1

* Update bullet to version 5.5.1

* Update domain_name to version 0.5.20170404

* Update letter_opener_web to version 1.3.1

* Upate redis-rails to version 5.0.2

* Update active_record_query_trace to version 1.5.4

* Update capistrano-rails to version 1.2.3

* Update dotenv-rails to version 2.2.0

* Update pg to version 0.20.0

* Update tilt to version 2.0.7

* Update warden to version 1.2.7

* Update tins to version 1.13.2

* Update terminal-table to version 1.7.3

* Update oj to version 2.18.5

* Update simplecov to version 0.14.1

* Update uglifier to version 3.1.13

* Update hashdiff to version 0.3.2

* Update webmock to version 2.3.2

* Update devise to version 4.2.1

* Use ruby version 2.4.1

* Update sass to version 3.4.23

* Update puma to version 3.8.2

* Update will_paginate to version 3.1.5

* Update font-awesome-rails to version 4.7.0.1

* Update fuubar to version 2.2.0

* Update pry-rails to version 0.3.6

* Update simple-navigation to version 4.0.5

* Update rubocop to version 0.48.1

* Update doorkeeper to version 4.2.5

* Update faker to version 1.7.3

* Update aws-sdk to version 2.9.5

* Update fabrication to version 2.16.1

* Update hamlit-rails to version 0.2.0

* Update http to version 2.2.1

* Update httplog to version 0.99.2

* Update sidekiq to version 4.2.10

* Update rspec-sidekiq to version 3.0.0

* Update pghero to version 1.6.4

* Update rack-cors to version 0.4.1

* Update i18n-tasks to version 0.9.13

* Update ruby-oembed to version 0.12.0

* Update jquery-rails to version 4.3.1

* Update simple_form to version 3.4.0

* Update react-rails to version 1.11.0

* Update aws-sdk to version 2.9.6

* Update sidekiq-unique-jobs to version 5.0.0

* Update uglifier to version 3.2.0

* Use HTTP Accept-Language to detect locale

* Fix gem order to comply with codeclimate

* Sort gem to comply with rubocop

* I18n.default_locale fallback when there is no accept-language header

* Rewrite Atom generation from stream entries to use Ox instead of Nokogiri::Builder

StreamEntry is now limited to only statuses, which allows some optimization. Removed
extra queries on AccountsController#show. AtomSerializer instead of AtomBuilderHelper
used in AccountsController#show, StreamEntriesController#show, StreamEntryRenderer
and PubSubHubbub::DistributionWorker

PubSubHubbub::DistributionWorker moves n+1 DomainBlock query to PubSubHubbub::DeliveryWorker
instead.

All Salmon slaps that aren't based on StreamEntry still use AtomBuilderHelper and Nokogiri

* All Salmon slaps now use Ox instead of Nokogiri. No touch from status on account

make regeneration worker unique, (only schedule/execute once at a time)

Try to fix Travis CI setup

improved how "show more" link looks

with YAML-defined defaults. Add admin page for editing global settings. Add "site_description"
setting that would show as a paragraph on the frontpage

fix bug in process feed service

Fix #233, fix #268

can be processed separately