Site nav enhancements (hashrocket#759)

* Move site nav html to top of body

This makes it more accessible for screen readers and tabbing through the
page

[Fixes hashrocket#641]

* Use display property for toggling search form

This enhances tab navigation as its not tabbing through
"hidden" elements

Merge pull request hashrocket#262 from hashrocket/add-reason

Add a task to create the ReasonML channel

Merge pull request hashrocket#242 from hashrocket/autoformat-lib/tile…

…x_web/controllers/stats_controller.ex

Autoformat lib/tilex_web/controllers/stats_controller.ex

Merge pull request hashrocket#231 from hashrocket/autoformat-lib/tile…

…x/notifications/notifiers/notifier.ex

Autoformat lib/tilex/notifications/notifiers/notifier.ex

Merge pull request hashrocket#191 from hashrocket/feature/twitter_cards

Twitter user sees channel specific twitter card

Remove extra curly bracket

Merge pull request hashrocket#187 from hashrocket/feature/streaks

Mix task to show current streaks

Merge pull request hashrocket#171 from hashrocket/fix/random-post-path

Fix/random post path

Merge pull request hashrocket#165 from hashrocket/issue-160b

Only show Twitter button on post show, close hashrocket#160

Merge pull request hashrocket#156 from hashrocket/implement-page-objects

Implement page objects