Add contact page to practice page
practice: Fix rendering issue for phone number form field

Increase the minimal width requirements of the right column to
render the phone number form field on one line; affects
Mobile Safari (iPad, iPad Retina).
Implement logic for site-wide contact form processing

* Disable search_results site page.
* Add express-session, connect-flash dependencies.
* Update README to reflect the addition of the SESSION_SECRET
environment variable.

* Replace res.locals.notifications with connect-flash; this allows us
to store and pass notification (err) messages to any defined router.

* Relocate contact form processing to lib/form_helpers.js; this lets us
call it from anywhere within our app (i.e.: contact form on the home
page, practice page, contact us page).

* Revamp contact.jade to use contact_form.jade (via template inclusion).

* Remove the passing of local input_errs object; this was long overdue!
It was obsolete the moment we declared the list of possible errors in
res.locals.input_errs (see app.js).

* Increase the font size and decrease font weight of error messages.
Remove last name field, rename first name to name
index.jade: Add stub hyperlink to 'Find Out More' button link