small adjustments to the theme for site messages plugin update

[rybridge]

Small adjustments to the theme and how it interacts with the site messages plugin.

• Adds the popup region below the tag
• Register the region
• Adjust homepage middle markup. This markup was moved into the plugin itself
• Sets up our cookie for "session" tracking
• Registers Session count in the admin for the conditional criteria
• Removed the site header file. It seems pretty much the same as the file that was in the plugin. But maybe I'm wrong
• Not sure how that spacing adjustment happened in the normalize.scss file, but just left it.

[jonathanstegall]

Tagging issue #21, as this is part of it.

[rybridge]

Anything else I need to look at here or is this approved? Not sure how to proceed since it got tagged as a part of an issue.