Updated Devise 'locked' message from 'Invalid email or password' to 'Invalid username or password'
Updated login icon from envelope to user
Merge pull request #196 from pophealth/login_ui_updates

Login ui updates
Make username and email show up as required fields.
Update registration page to reflect actual database requirements.
Strip unnecessary characters and backslashes from the bundle.
Account info page subtext was incorrect, min username length is 3 characters.
Update icons in Account info page to match the registration page.
Add string for unapproved users.
Added padding to subtext.
Cleanup password fields and update subtext.
Render the shared header instead of duplicating the logic in the edit page.
Hide password confirmation field unless user is changing their password.
Username and email should show as required fields in the account info page.