Added new folder "styleguide", put typography HTML file inside.

Renamed “type-guide” HTML to “typography.”
Added CSS and HTML file for "buttons" in style guide.
Added css and font links to HTML head.
Added HTML code for the buttons.
Created CSS for two different button variations.
Create list-group CSS file.
Added styles to list-group CSS file.
Created HTML and CSS files for product list item.
Created CSS file for media object.
Added code to media-object CSS file.
Added code to HTML for product list item.
Changed CSS link to proper name.
Made changes to product list CSS.
Modified type and list items in product list HTML.
Changed style for list-group CSS file.
Created CSS file and HTML files for the promos.