Disable un-used fonts, scripts
Bit of security hardening

* Add Helmet app dependency.
* Remove crossdomain.xml; we now use Helmet's default served file.
* Ensure that our session cookie's 'httpOnly' member is set to true.
Misc clean up

* about.jade: Add page title.

* contact_form.jade: Add contact_form class onto form element's class
list.

* error.jade: Add support email link.
Fix HTML5 validation errors
Clean up form validation errs for phone number
Re-add display of the number of validation errs found

* contact_form.jade: Add errs anchor & action link for jumping
to the number of validation errors message upon form submission.

* contact_form.jade: Fix layout issue by re-adding the input_container
class within a div; the widths for the form elements must inherit from
the parent (input_container), otherwise we are ~4% over on the right
margin.
Do not open links in new window ;-/
Use contact form's recipient address for smtp from header
Use checkmark for list image style on home page
Use redis session store for production setup

This resolves the warning message issued upon web app startup:

"Warning: connect.session() MemoryStore is not designed for a production
environment, as it will leak memory, and will not scale past a single
process."
Bit of clean up in lib/form_helpers.js

* Remove or disable (comment) un-used variables,
functions.

* When errors, log regardless of app
environment.

* Fix the generated email's FROM field.

* Add an err check for when the JSON response
message is not 'success'.
Append 'novalidate' to contact form if not in production env
Temporarily disable Redis session store
Update sitemap.txt
Wee bit of internal clean up for stylesheets
Improve subject line of generated emails
layout.jade: Remove old comment
Add keys/* to ignore filter
Fix use of Redis session storage

* app.js: Use MemoryStore session storage for 'development', local Redis server for 'testing' and RedisCloud (Heroku add-on) for 'production' environments.