Align stylesheet style with Twenty Thirteen

Added table of contents and section titles, merged old styles with the
new stylesheet, added placeholders as to dos
First pass at cleaning up navigation menu styles

Switched to classes, applied coding standards
Added Genericons icon font
First pass at content.php

Basic functions and styles to display blog posts.
Updated gitignore to exclude .DS_Store files
First pass at the Aside, Link and Quote Post Formats
Rough Pass over the Sidebar and the Comments

Needs finetuning
Quick pass over the remaining Post Formats

Adapted tp the new updated 3.6 API functions