consolidate relatedTarget docs in dropdown event docs
corrects IRC room
Don't line wrap event names in JS plugin docs
escaped uri
Specify `img` alternative text.
Expand caveat for disabled fieldsets and links
Redundant role="form" on <form>s
Redundant role="navigation" on <nav>s

plus one example that still used the old <div role="navigation"> and a
fix-up of the callout as per
https://github.com/twbs/bootstrap/issues/15109
Fixes to scope

as discssued in
https://github.com/twbs/bootstrap/issues/15117#issuecomment-63029993

- added ``scope="row"`` to row headers
- made sure row headers are actual ``<th>`` elements
- removed ``scope="col"`` where it was redundant
- simplified table examples with (to me) unnecessary
``rowspan``/``colspan`` (unless you really want complex tables, in which
case we would need full-on ``id`` and ``headers`` attributes to make
sure each table cell has an explicit association with the related header
cells - overkill, in my opinion)
- one table (in typography) left header-less, as it's more or less presentational (though its structure is still important, hence not adding ``role="presentation"``)
Move context-specific callout to general tag usage
Move button-tags section to start of button section
upgrade OS X tests to Yosemite

[skip validator]
Merge pull request #15149 from twbs/yosemite

upgrade OS X tests to Yosemite
upgrade iOS tests to 8.1

[skip validator]
Merge pull request #15150 from twbs/ios-8.1

upgrade iOS tests to 8.1
add unit tests for Carousel's 'wrap' option
honor wrap option in Carousel.getItemForDirection; fixes #15144
Add modal autofocus example
Merge pull request #15135 from hillai/patch-1

Add modal autofocus example
Merge pull request #15139 from patrickhlauke/docs-button-section-restructure

Docs button section restructure