Add screenreader text to prev/next carousel buttons in examples to improve accessibility

add role="listbox" to .carousel-inner to improve accessibility of Carousels

Refs #13556.
Per https://github.com/paypal/bootstrap-accessibility-plugin/blob/master/README.md#carousel
Credit: https://github.com/paypal/bootstrap-accessibility-plugin

[skip sauce]

Refs #13556.
Per https://github.com/paypal/bootstrap-accessibility-plugin/#carousel
Credit: https://github.com/paypal/bootstrap-accessibility-plugin

[skip sauce]

Jekyll: Use non-minified assets when not running from GitHub Pages

Add role="tablist" to .nav-pills in examples to improve accessibility

Follow-up to e9374c06
Per https://github.com/paypal/bootstrap-accessibility-plugin/commit/f203dea4b6d17264d7b776f02feaeeaa386cc9b2
Credit: https://github.com/paypal/bootstrap-accessibility-plugin & @rohk

[skip sauce]

remove Glyphicons docs autogeneration from Grunt

Simplifies the build tooling a teeny bit.
This data file shouldn't need to be updated for v3 ever again.
This task will also be unnecessary in v4.

[skip sauce] [skip validator]

Follow up to #13907: Add .focus styles for buttons

Address margins on .navbar-right to fix #13325 #13464.

add "focus" to focused btns with button plugin

Fix small typo introduced in e2029e12

Add touch-action: manipulate to .btn

This commit follows f9fde567.

Major unit tests cleanup

Add collapsed default class to navbar-toggle