Flint 1.0.0 Release Candidate 5

Bugs
- [x] Update post formats to be accurate
- [x] Update `.badge` to `.label` to preserve colors
- [x] Correct Theme tags in description
- [x] Update `flint_posted_on` for better display
- [x] Fix `<video>` to have a `max-width` of `100%`

Misc
- [x] Simplify titles on archive pages
- [x] Change default header image to white
- [x] Remove pink from style.css
- [x] Add post format gallery template
- [x] Add space between articles and remove `<hr>` between articles
- [x] Simplify `steel_open` code in `header.php`