properly integrate Rouge into the Travis build; fixes #14078

[skip sauce]
Merge pull request #14083 from twbs/fix-14078

Properly integrate Rouge into the Travis build
add role="presentation" to tab <li>s to improve accessibility

Refs #13554.
Per https://github.com/paypal/bootstrap-accessibility-plugin/blob/master/README.md#tab-panel
Credit: https://github.com/paypal/bootstrap-accessibility-plugin

[skip sauce]
Add role="tabpanel" to .tab-pane <div>s to improve accessibility

Refs #13554.
Per https://github.com/paypal/bootstrap-accessibility-plugin/blob/master/README.md#tab-panel
Credit: https://github.com/paypal/bootstrap-accessibility-plugin

[skip sauce]
Merge pull request #14086 from twbs/tab-pane-role-tabpanel

Add role="tabpanel" to .tab-pane <div>s to improve accessibility
Merge pull request #14085 from twbs/tab-lis-role-preso

add role="presentation" to tab <li>s to improve accessibility
add role="tabpanel" to .panel-collapse to improve accessibility

Refs #13555.
Per https://github.com/paypal/bootstrap-accessibility-plugin/blob/master/README.md#collapse
Credit: https://github.com/paypal/bootstrap-accessibility-plugin

[skip sauce]
Add role="tablist" & aria-multiselectable="true" to accordion .panel-group to improve accessibility

Refs #13555.
Per https://github.com/paypal/bootstrap-accessibility-plugin/blob/master/README.md#collapse
Credit: https://github.com/paypal/bootstrap-accessibility-plugin

[skip sauce]
Merge pull request #14088 from twbs/panel-collapse-role-tabpanel

add role="tabpanel" to .panel-collapse to improve accessibility
Merge pull request #14089 from twbs/accordion-panel-group-aria-multiselectable

Add role="tablist" & aria-multiselectable="true" to accordion .panel-group
Fix invalid HTML in "should allow html entities" tooltip unit test

Refs #14090.
Also, fix one typo.
Merge pull request #14091 from twbs/tooltip-test-html-fix

Fix unusual HTML in "should allow html entities" tooltip unit test
Fix IE8 reporting height style as all uppercase
Fix IE8 reporting type object for `getBoundingClientRect`
`document.head` is undefined in IE8
Merge pull request #14090 from hnrch02/unit-tests-ie8

Fix IE8 problems with unit tests