refactor(rating): use optional binding for `readonly`

Closes #1641
demo(dropdown): remove unneded data-* attributes
refactor(collapse): removed unused di parameter

Closes #1633
test(accordion): remove unused variable

Closes #1646
test(alert): remove unused controller parameter

Closes #1647
test(datepicker): remove unused variable

Closes #1648
test(tooltip): remove unused injection

Closes #1649
test(tooltip): remove more unused code

Closes #1650
refactor(typeahead): remove unused code

Closes #1651
fix(modal): destroy modal scope after animation end

Fixes #1643
fix(moadl): toggle 'modal-open' class after animation

Fixes #1629
chore(readme): add support section

Closes #1655
fix(modal): backdrop z-index when stacking modals

Previously, backdrop wouldn't go over the previous open modal when a
modal is open on top of another.

Fixes #1653
Closes #1654