Refactor mailers.

Conflicts:
	app/controllers/account_controller.rb
Redesign and reword emails.

Includes the use of premailer to send both html and text parts.

Conflicts:
	Gemfile.lock
	config/routes.rb
Wrap signup in transaction.
Merge pull request #18 from wvengen/feature/pretty-emails-upstream

Refactor and reword emails.