Exempt Dropbox links from being tagged

Both dl.dropbox.com/u/ and dl.dropboxusercontent.com/u/ are being
snagged unintentionally.
Update loadAllInAlbum description

..to make its purpose a little more clear.
Prevent duping of username hider text

Workaround for Hover Zoom whereby it can destroy the title attribute.
This breaks the current selector, causing the username to be injected
into the link/comment karma counts.
Fix for 'missing' styles on username hider

before/after content doesn't inherit the user highlighter styles, so
those with the username hider enabled just get white text when OP/Mod,
making it seem invisible.
Combine loggedInUser calls from 07047f6
Username hider - add created/curated by support

For the 'created by' at the bottom of subreddit sidebars and the
'curated by' on multireddit pages.
Merge pull request #526 from gavin19/master

Exempt Dropbox links from being tagged, various username hider tweaks