Added a user controller to handle user actions

This will control both user login and sign up.  I am totally excited
about this.
Two new partials in and index modified
Layout into the user controller
Survey list view in
Centered any content in the body of pages
Added all forms no styling
Added two classes to help center content

You can now use these in conjunection to center content in the middle of
the screen.  Please see the examples of where I use them if you want to
understand how / why they work.
OO CSS FOR THE WIN

All styles and forms in for user sign up and sign in.  Moving onto logic
next and then rotation.
Merge pull request #13 from zachgersh/sign_up_forms

Sign up/Sign in forms.  
you #killedIt