Fix post breadcrumb styles and text.

This fixes the breadcrumb styles.

Before: http://d.pr/i/zwcy
After: http://d.pr/i/mRBi

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- Qualify nav styles to apply only to sidebar nav.
- Make breadcrumbs use skeleton button styles.
- Fix commented twitter and facebook elements to include the closing
  div tag.
- Add .hyde_deps to gitignore.

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