#1762 and then some

includes / fixes #1762 

also hides other usernames at the same time
also pulls usernames from account switcher for hiding
The display text is also used as HTMLElement text content, not just CSS content -- specifically for multireddit sidebar's "curated by /u/...".  So, we'd have to do return a pair of values or do some other conversion for `\00A0` to `&nbsp;`