Remove unnecessary includes, finish renaming set_header_data, only run set_header_data on html requests

do not escape html in private_message text only email

Conflicts:
	app/controllers/status_messages_controller.rb
	app/models/data_point.rb
	app/models/status_message.rb
	db/schema.rb
	lib/fake.rb
	public/stylesheets/sass/application.sass
	spec/models/mention_spec.rb