Add suport for <!--no-paging-->

Issue Summary

I'd like to be able to add a <!--no-paging--> tag to content to tell the page module that I don't want this content paged at all (same effect as the /full option). The underlying issue is that sometimes I just want one long page but with auto page breaks on I can't get there (putting a page break at the end just yields an empty second page which could be considered a bug in itself.). Right now I'm solving this with a second input format that doesn't use the paging filter but that's a kludge IMHO.