bitbake: user-manual-hello.xml: Added new chapter for "Hello World Example"

bitbake: user-manual-hello.xml: Added new chapter for "Hello World Example"

This file was evidently a "working" file and not included in the
manual at the point Bill left off.  The wmat branch, however, had
a load of commits dedicated to this file.  Rather than attempt to
replay them all one-by-one, I simply copied the file from the
wmat branch and hand-inserted the changes to make it equal to what
was there.  Note also that I re-formatted the file to have the
same formatting standards I use in the YP manuals.

(Bitbake rev: 9ddbf31ba7d05a596ca53b8ed78d94221850894b)

Signed-off-by: Scott Rifenbark <scott.m.rifenbark@intel.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>