local.conf.sample : Add tune setting for zc702 and fix images for wic.

wic uses intermediate build output that is normally removed by the
rm_work class. Stop rm_work for running for image recipes.

Signed-off-by: Philip Balister <philip@balister.org>
Add a wks file for 8G sd cards.

wic normally calcualtes the size of a partition based on the amont of stuff
installed plus an overhead factor. This hard codes the the size for an 8G sd
card. This is good and bad, bad in that it takes a long time to write, good
in that you do not need to figure out how to resize the partition.

Signed-off-by: Philip Balister <philip@balister.org>
build-all.sh : Add a script to show how to build complete images.

I use this script to create files for gnuradio users.

Signed-off-by: Philip Balister <philip@balister.org>