code.less: also set default monospace font for `<kbd>` and `<samp>`
Fix #10324: Add opt-in note to tooltip docs

* Re-added a note (now callout) about need to opt in to tooltip docs
* Converted same note in popover section to callout
changed attr('data-target') to data('target');

this will extend js interface, to be possible to setup targets for tabs as 
    var content=$('<div class="tab-pane">',{text: 'content'});
    var tab=('<li>',{html: $('<a>',{text: 'Main options'})}).addClass('active').data({target: $main,toggle: 'tab'}).appendTo(tabs);
Match order of vars to order of components; darken some alert borders
Add Welcome section to docs

* Fixes unrelated typo in readme
* Add new Welcome section with history, team, callouts, and community
subsections
* Redesigns callouts to be a bit lighterweight with colored headings
shorter avatar urls
use irc link
fixes #10526: Remove custom background on responsive tables and set it in the docs where it should've been originally
Merge branch 'master' into docs_welcome
adding required attribute for example signin form
Copy edits from @cvrebert and @juthilo
dat @juthilo edit
dat hash
add .control* to migration docs; fixes #10532
Merge pull request #10542 from twbs/controls-migration-docs

add .control* to migration docs; fixes #10532
fixes #9985: update grid classes in grid example
Fix #10556

Make media queries example in docs clearer
Remove display: block from address

<address> is already displayed as block in all browsers (UAs).
Rephrase text
add missing comma in carousel.less; fixes #10562