allow require.resolve('bootstrap') to work under node
added 'main' field to package.json
added a separate npm-specific main file
Change value of stateful button after event loop

Fixes #14450
generate commonjs/npm entrypoint module via grunt task
Merge remote-tracking branch 'upstream/master' into node-requirable

Conflicts:
	Gruntfile.js
pulled output path out to gruntfile
code style fixes
added banner about generated file
code style improvement
Use e.target instead :focus selector.
Added link hover decoration variable
Allow to scroll the nav

Basically it's impossible to use the navigation if it's expanded. This will allow it to be scrollable so that the menus are accessable.
Fix #14856

[skip sauce]
Add jQuery version check to existing jQuery presence check

Fixes #14809.
Closes #14825.
Merge pull request #14669 from vsn4ik/dropdown_event_target

Use e.target instead :focus selector.
Merge pull request #14852 from twbs/jquery-version-check

Add jQuery version check to existing jQuery presence check
grunt
Fix a small typo in comment.

[ci skip]
Docs: Use a 180x180 apple-touch-icon.png.

Refs:
https://github.com/h5bp/html5-boilerplate/commit/1c4fcf32142e888946db579df0efbb52542e0ed1
https://github.com/h5bp/html5-boilerplate/commit/345925f04384b59929d8d39ba428cef548921408

[ci skip]