Locked notes fix + More notices

* Added several more options for hiding notices.
* Fixed potential cache problems that might come up if a user clears their browser's cache.
* Fixed "alternate image swap" so that it doesn't break itself and notes on posts with locked notes.

I'm using XPath for some of the notices since they lack any definite way to identify them (ID, etc). They might be vulnerable to breaking (as in "not working" and not "errors") on updates, but at least they won't accidentally hide anything.