Rearranged a few sections, add memoryuse section.

Added a <label>s for cross reference targes.

Lots of editing, added cross references to other sections of
the handbook.  Added a sample BSD-style copyright statement.

Updated the mailing list section, thanks to Peter Dufault.

Added Peter Dufault, David Greenman and Joerg Wunsch.

A new section about how/where in PC memory the FreeBSD kernel
gets loaded and run.