* Update docs to include table of grid levels and behaviors
* Change from .col-md to .col-sm to match existing size variables we use elsewhere
* Keep .col-lg as-is though for simplicity as we won't likely add a fourth level of the grid
* Combine responsive .container breakpoints with grid breakpoints in grid.less
* Other misc docs updates
- Removed mixins for generating grid classes
- Thus, we manually declare every grid class, from 1-11 (12th unit is
excluded as that's the same as no grid columns)
- No more need for `.col` base class (yay!)
- Negative indent the rows at tablets and above once again (ugh, still
working through this part)
- Add support for `.col-md` for tablet-specific grid columns
- Still need to figure out offsets, pushes, and pulls on other
devices—right now only available on desktop
* Add start and end support to the horizontal gradient as well
* Change all variables from camelCase to use-dashes
* Better comments in the gradients mixins area
* Update current uses of gradients in dropdowns and carousel to specify only two values by direct assignment of variables
* No more children selectors to set all links in alerts as a special color because buttons and more wrongly inherited color
* Adds .alert-link for easy styling in any alert
* New padding approach with separate horizontal and vertical padding
variables
* Improved sizing in large and small buttons and form controls
* Dropped the `.btn-mini` (since we have no `.input-mini` to match, and
holy fuck those were small buttons)
* Dropped the `.pagination-mini` as well because once again, to hell
with such small components
* Changed `@line-height-headings` to `@headings-line-height`
* Removed the `@headings-font-family` because it was honestly kind of
useless
* Remove border-radii on top of tab dropdown menus
* Remove the .dropdown and .dropup styles and instead place on all
* Use on dropdown carets intead of separately applying margin with a top alignment
* Some other misc cleanup
