[oe] sourceipk.bbclass patch submission

[Chase Maupin]

All,

This e-mail is to describe the purpose of the patch that will
follow which adds a sourceipk.bbclass file to the classes
directory.  The purpose of the sourceipk class is to allow
recipe authors and openembedded users to create a simple
ipk package that contains the patched sources and recipe
used to create the binary ipks.  This source ipk does NOT
build the binary ipks itself, that is still done using
bitbake and openembedded.

The purpose is to allow the sources to be placed in a
feed along with the binaries and installed on either the
target system for native building or the host system for
reference on manual cross compilation if desired.

This can also be used by installers that will install/create
custom images and their corresponding sources based on user
selection.

Please consider the patch that follows for inclusion.  I would
also like to take this time to thank Koen and Denys for their
input and feedback on this code.

Sincerely,
Chase Maupin