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

Depending on the git setup, if the `git diff` is used on the command line, I believe it shows trailing whitespace by default, see http://git-scm.com/book/en/Customizing-Git-Git-Configuration core.whitespace.

For sublime text 2, I have these set in my user preferences, which usually gets rid of extra whitespace on save:
```
	"trim_automatic_white_space": true,
	"trim_trailing_white_space_on_save": true
```

Note that it can cause issues with trailing whitespace in an l10n file, but we have gone to typing out `\u0020` in those files when they are needed, to avoid any whitespace trimming issues.