MFbed: Content update and various fixes.
books/handbook/kernelconfig/chapter.sgml 1.99 -> 1.100
books/handbook/cutting-edge/chapter.sgml 1.180 -> 1.182
books/handbook/mirrors/chapter.sgml 1.274 -> 1.277
books/handbook/pgpkeys/chapter.sgml 1.188 -> 1.190