v4 Input Group height problem

Created by: anthonyvalera

Hey all,

I ran into two minor issues in v4 Input Group documentation and figured I'd put them in one issue.

Input group sizes are styled incorrectly in Chrome Version 44.0.24 and Safari. input-group-sm is working in Safari, input-group-lg is not.

Dropdowns on this page have v3 markup.

I can try to setup and submit a pull-request if needed. v4 looks great btw!