Bug 800402 - [email] UI: Show the number of unread messages in the message-list header after the folder name

Corresponding PR in gelam is here: https://github.com/mozilla-b2g/gaia-email-libs-and-more/pull/315
Both the manual positioning and the setTimeout here are somewhat confusing/non-intuitive here.  If they are truly needed, comments are definitely in order.  I see @jrburke mentioned adjustHeaderMargins in his previous review, but any discussion appears to have occurred outside of bugzilla/github, so I'm missing the context.

Reverse-engineering from the code, it seems like the intent is to add roughly equivalent padding to the other side of the name so that centering of the folder name itself is maintained and the numeric badge is affixed to its right.  While this potentially provides visual stability, it may also result in visual jumping because of the use of setTimeout.

I'd suggest we get clarification from VD that they don't want the unread count to affect the centering of the folder name.  We should also especially ask about what they think makes sense in the case where the folder name is very long since the English "Inbox" is a comparatively short folder name.