fix(select): auto-select new option that is marked as selected

When adding a new <option> element, if the DOM of this option element
states that the element is marked as `selected`, then select the new
<option> element

Closes #6828
Merge branch 'master' into issue-6828

Conflicts:
	src/ng/directive/select.js
Merge pull request #7136 from lgalfaso/issue-6828

fix(jqLite): Chrome specific issue for `<select required>`