Fixes #11669 - Adds smooth modal scrolling on iOS by default
Drop redundant module import
Merge branch 'master' into pr/11776

Conflicts:
	package.json
Merge branch 'master' into pr/11676

Conflicts:
	less/modals.less
run grunt on modal scrolling change
revert an earlier change to move the component-animations.less file because it fubared modal backdrop .fade usage
Merge branch 'master' of github.com:twbs/bootstrap