add button to toggle the optional theme when viewing the docs; fixes #9764
regenerate minified docs JS & CSS
Adjust for Scrollspy offset when calculating maxScroll.
Add Scrollspy maxScroll with offset test.
Add tooltip self-reference to address #12320

primarily adds a data- attribute to the tooltip (and thus, the popover)
to create a self-reference.
Adds aria described by to tooltip plugin for accessibility

Generates a unique id for tooltip and adds [aria-describedby] to the element
it is called on. Resolves issue #13480

- set up test
- linted the code styles
- passed the tests
- integrated feedback from @cvrebert
add missing event namespacing in modal.js
add to TRAVIS_COMMIT_MSG, TWBS_DO_VALIDATOR, TWBS_DO_SAUCE vars to Travis
Travis: skip RubyGems install+cache when TWBS_DO_VALIDATOR=0
Gruntfile: extract runSubset() func
Gruntfile: skip steps when $TWBS_DO_*=0
prove that [skip sauce] works

add extra newline to .travis.yml that I'll remove momentarily
prove that [skip validator] works

removes the extra newline added in the previous commit
Merge pull request #13623 from twbs/skip-ci-steps

add [skip sauce] and [skip validator]
Reassigned minification of CSS to cssmin task.

Reassigned minification of CSS files from the less task to the cssmin
task
Merge pull request #13615 from twbs/namespacing

add missing event namespacing in modal.js
fix typo in assertion description
Merge pull request #13624 from robertdodd/master

Reassigned minification of CSS files to the cssmin task.
Merge branch 'master' into docs-theme-toggler

Conflicts:
	docs/assets/css/docs.min.css
update explanatory comment about iOS date/time inputs bug

Per:
* http://jsbin.com/purer/2/edit
* https://github.com/cvrebert/bs-css-hacks/blob/6e8aa78384a005b007fc45327c9516dcf6ec0f30/README.md#ios-temporal-input-line-height
Thanks @mdo <3

[skip sauce] [skip validator]