Add Google Analytics, authentication file.

Add:
        static/js/main.js
                -Add a global javascript file, with bitshift's Google Analytics
                snippet.

        static/google10335120a3066831.html
                -Add our Google "Administrator Console" authentication.
Remove hard-coded file routes.

Add:
        app.py
                -Remove hard-coded routes for files in the application's "root"
                (`static/`) directory; redefined Flask's `static_url_path`
                accordingly. Files can now be directly accessed by URL.

        bitshift/assets.py
                -Remove the `static/` prepended to all resource paths.
Add 404 page. Minor footer-style mod.

Add:
        app.py, templates/error404.html, static/sass/error404.sass
                -Add Flask 404 handler and styled 404 page.
Merge branch 'feature/seo' into develop

Add search-engine files, a favicon, and 404 page. Close #70, #71.