Editor/title buttons need horizontal padding on Sourcegraph

Created by: ryan-blunden

Sourcegraph version: 25726_2018-12-18_8277ea5 (25726_2018-12-18_8277ea5) Sourcegraph browser extension version: v18.12.13.848 Platform information: macOS Majova, Chrome 71.0.3578.98

Steps to reproduce:

1. Publish and enable Python Button
2. View a python file

Expected behavior:

Buttons are spaced nicely

Actual behavior:

Buttons are too close, and there is no spacing between the icon and label