twitter/bootstrap — pull request #1853 by jsmecham (2012-02-09 00:16:48+00:00)
Title: Properly align buttons (including btn-navbar) in the navbar for custom heights

Buttons within the navbar are given a static top margin value of 5px, which assumes that the navbar has a height of 40px. Changing the height of the navbar results in buttons that are not vertically aligned.

This patch still hard-codes the assumed button height, which I dislike, but I don't see it as any worse than hardcoding the margin for 40px assumed height of the navbar.