Syntax highlighting of LinuxMMDocumentation

For now just the content copied from the old linux-mm site.  Please update and include links to Linux memory management documentation elsewhere.

 * VirtualMemory an irc log with answers to often asked questions.
 * HighMemory or how the Linux kernel can use more than 1GB of physical memory.

== External documents ==

 * Joe Knapka's [http://home.earthlink.net/~jknapka/linux-mm/vmoutline.html Outline of the Linux Memory Management System], which is mostly about the 2.4 kernel.