A simple Reload button, for those who want one to the right of the Address Bar. (Stop function not included; see below.)
To save RAM, the extension uses an event page rather than a persistent background page. Hopefully it won't lag during heavy disk access.
For a Stop button, see:
0.4: Updated icons to match Chrome's new Material theme.
0.3: Removed "tabs" permission. Turns out it isn't needed to call chrome.tabs.reload.