add a StaticPages controller
add tests for static home and help pages
add initial home and help static pages
add test for static about page

* Add initial test for static "About Us" page
* change tab size from 4 spaces to 2 spaces in spec file
add initial about static page
add tests for static pages titles

Add tests to check the titles of the following static pages:
* check title for home: "Twitl | Home"
* check title for about: "Twitl | About"
* check title for help: "Twitl | Help"
eliminate duplication in static page code