[card] header and footer variants & classes (#463)
[card] header and footer variants & classes (#463)

* [carousel] Fixed this arg in forEach

Should address issue #396

* [carousel] coerce querySelectorAll into an array

Coerce slide nodelist into an Array

* [carousel] ESLint

* [input-group-addon] conditional ID on root element

* [nav-item-dropdown] add ID to root element

* [card] Header and footer variants & classes

Allow contextual background variants on headers and footer, and allow user to apply arbitrary classes to headers and footer.

* [card] ESLint

* Update input-group-addon.vue

wheldring/bootstrap-vue-compiled,tmorehouse/bootstrap-vue,mosinve/bootstrap-vue,sschadwick/bootstrap-vue,sschadwick/bootstrap-vue,bootstrap-vue/bootstrap-vue,mosinve/bootstrap-vue,wheldring/bootstrap-vue-compiled,SirLamer/bootstrap-vue,bootstrap-vue/bootstrap-vue,sschadwick/bootstrap-vue,tmorehouse/bootstrap-vue,SirLamer/bootstrap-vue,wheldring/bootstrap-vue-compiled