Revert using user-defined email address for FROM header

On second thought, this was clearly a terrible idea (due to blacklists,
and the like) -- think: SPAM.
	The HTML email template has been updated to link the user-defined
email address for quick-n-easy reply.
contact_success.jade: Replace Lorem Ipsum text
Address several contact form styling issues

* style.css: Fix width & margins issue on mobile devices for contact
input fields.
* style.css: Use font-family 'Arial' as default for all input field
types; the rendering of certain characters (i.e.: capital J) looks
funny to me (when using 'Open Sans')...

* contact_form.jade: Fix layout issue with alert icon & wrapped text.

* contact_form.jade: Rename 'Your Full Name', 'Your E-mail Address'
input fields to 'Your Name', 'Your Email Address'.
* contact_form.jade: Use explicit 'Required' label text for marking
required input fields.

* Introduce rescaled alert icon sizes: alert_24.png, alert_32.png.
  Rename alert.png to alert_48.png.
* contact_form.jade: Use smaller alert icon (use alert_32.png).

* contact.js: Re-declare mock_errs as an app-wide variable (see app.js)
for ease of access.
Specify width & height for all img elements

* This lets the browser do page layout (much) earlier in the
loading process.