Add JSHint javascript linter

Gemfile

Gemfile.lock

app/assets/javascripts/app/app.js

app/assets/javascripts/app/helpers/truncate.js

app/assets/javascripts/app/models/post/interactions.js

app/assets/javascripts/app/models/stream.js

app/assets/javascripts/app/views.js

...javascripts/app/views/aspect_membership_blueprint_view.js

app/assets/javascripts/app/views/aspect_membership_view.js

app/assets/javascripts/app/views/aspect_view.js

app/assets/javascripts/app/views/aspects_dropdown_view.js

app/assets/javascripts/app/views/aspects_list_view.js

app/assets/javascripts/app/views/contact_view.js

app/assets/javascripts/app/views/content_view.js

app/assets/javascripts/app/views/hovercard_view.js

app/assets/javascripts/app/views/profile_header_view.js

...sets/javascripts/app/views/publisher/poll_creator_view.js

app/assets/javascripts/app/views/publisher/uploader_view.js

app/assets/javascripts/app/views/publisher_view.js

...ts/app/views/single-post-viewer/single_post_moderation.js