Pool gallery CSS & Thumb limit updates

* Moved the test for hidden posts to its own function so it can be used on thumbnail listings not currently in the document.
* Updated the thumbnail limit retrieval portions by creating a main function for getting the value and changing the function for getting the limit metatag from the URL's query string to a general function for retrieving the value of any metatag in the query string's tag portion.
* Updated the pool gallery view CSS in response to some changes and started using the previously added "bbb-thumb-link" class to make the CSS leave all other links in a thumbnail article alone.
* Replaced the horizontal rule dividing multiple notice message entries with some CSS.
* Swapped out window.innerHeight/Width with document.documentElement.clientHeight/Width for better support and values that don't include the scrollbars.