removed outline from modal
Customizable backdrop opacity
Added opacity to customizer and rebuilt customizer
Options of sizes added in modal
Adjust in modal size rules
Add well-border variable

Add a variable to allow the well border color to be specified.

The reason I'd like to see this included is that my companies styleguide
requires an explicit border color on well-like constructs. This variable
allows me to easily override the default to use that color.
Fix #11400 and #11431
Fixed single btn in btn-group-veritcal not being rounded
Reduce size of the visibility styles
Fixes #11669 - Adds smooth modal scrolling on iOS by default
Don't exclude fonts from bower installs

Excluding fonts/ from bower installs causes glyphicons to be
unavailable to projects using development Bootstrap LESS files.
Updated .scale() mixin so that it accepts optional vertical scale factor parameter.
reverted changes in commit 96109d3 which seemed to break conditional classes in striped tables (ignoring the comment above that the previous rules were needed for just this purpose)

fixes issue twbs/bootstrap#11728
Remove incompatible properties.
Lint docs-assets/js/application.js and docs-assets/js/customizer.js.
Fixes #11756: Mention document mode checking ability in IE comaptibility modes
Fixes #11729: Show code snippets on mobile views
Shorter download text because narrow viewports
prevent horizontal scroll on components
improve icon display on narrow devices