Add ability to turn off featuresets; add debugging code; misc.

- Featuresets may be turned on/off with BUILD_<NAME> = yes
  - Requires changes in kernel packaging repo
  - Make stamp names generic
  - When a target depends on a featureset-specific target, configure
    dependency with a variable
  - Pass unconfigured featureset names to script for configuring
    kernel pkg
kernel submodule:  pick up changes

commit 7ea8f4053c2a48b925bb50327e27e1788a28a25e
Author: John Morris <john@zultron.com>
Date:   Tue May 13 17:42:08 2014 +0200

    Add patch:  fix build error during module install

    make[6]: *** No rule to make target '/tmp/buildd/linux-3.5.7/debian/linux-image-3.5.0-1mk-xenomai-686-pae/lib/firmware/./', needed by '/tmp/buildd/linux-3.5.7/debian/linux-image-3.5.0-1mk-xenomai-686-pae/lib/firmware/atmsar11.fw'.  Stop.
    make[6]: *** Waiting for unfinished jobs....

    https://bugzilla.kernel.org/show_bug.cgi?id=39192
.gitignore:  ignore RTAI submodules without explicitly naming them