authenticates user logging in; adds flash/unflash methods to templater
adds user login and logout methods
moves AuthHandler register_user method to static method in User model
creates content partial and refactor way page content is rendered
moves page content partial from bootstrap theme folder to page handler folder
adds helper to page content view to vary tab display depending on whether is logged in or not
styles errors messages for auth form
styles flash alert messages
Merge pull request #8 from klenwell/q2SvSpvq-user-login

As a user, I want to be able to login with my user name and password.