Moving the embed to it's own CSS file, moving the docs to the Components page with an example, fixing a Glyhpicons list problem in the docs

* Adds nav link to sidebar for contextual classes
* Refactors to use prefixed classes, like .list-group-item-info, instead of chained classes
* Adds default and linked variations to example in docs

* Adds new section to navbar docs with example
* Updates example classes for all collapsing navbars so their numbers
increment as you scroll

Refactor alerts to have a base class, but no default class, thus requiring a modifier class at all times

finish up second pass through docs nav, headings, organization, naming, etc (another run through at #9710)

* Now responsive by default (fits better with mobile-first approach)
* Requires `.nav-header` to group `.navbar-brand` and `.navbar-toggle`
for proper mobile display.
* Changed `.nav-collapse` to `.navbar-collapse`
* Simplified examples in docs

Instead of applying `.btn-` or `.input-` to individual elements in
button and input groups, we now have new sizing classes to keep your
markup a little leaner.

* Add `.input-group-sm` or `.input-group-lg` to your `.input-group` to
replicate `.input-sm` and `.input-lg`, respectively.
* Add `.btn-group-xs`, `.btn-group-sm`, or `.btn-group-lg` to your
`.btn-group` to replicate `.btn-xs`, `.btn-sm`, and `. btn-lg`,
respectively.

Both sets of new sizing classes simply use the existing individual
sizing classes as mixins, so customization of them is automatically
inherited when compiling.

fixes #9310: alerts aren't dismissable by default, now requires .alert-dismissable if you need a close button

Fixes #9007 in a hopefully decent way

* Moves input groups CSS into separate file
* Moves input groups docs into the Components page
* Add support for radios and checkboxes in input groups to fix #8679

* Since we no longer have `.nav-list`, I've nuked the `.nav-header`
* However, dropdowns can still have section headings, so I've kept that
around with the addition of `.dropdown-header`
* Restyled it a smidge as well

* Fix alllll the links!
* Change all `*.js` in JS plugin docs (no mo `bootstrap-`)
* Fully remove `tr.info`
* Bring nav includes up to date

remove submenus. for more context: http://www.youtube.com/watch?v=ggWyUEuGcWY&feature=youtu.be&t=48s

* 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

* Bring back the navbar up top
* Pull the docs content back into separate pages because a 6.6k line docs file is just crazy
* Recenter the page content and bring back affixed side nav (needs work)