Enable armhf in live-build

[rsalveti, 2012-03-01] Thanks for putting up this blueprint, just please check and sync with Fathi about the enablement at jenkins, as it'll probably be the main client from this bp.
[tom-gall, 2012-03-06] Initial live-build a45 version under test ppa:tom-gall/packages
[tom-gall, 2012-03-06] cross ubuntu-desktop unlikely, still fails, 12.02 qemu fails(sig6), archive qemu ok
[fboudra], 2012-03-07] Tom, I guess you refer to "cross" with live-build-linaro. In my case, Debian qemu works with upstream live-build. I reported a bug against qemu-linaro: https://bugs.launchpad.net/bugs/947888
[rsalveti, Mar 28, 2012] Any update on the remaining WIs?
[rsalveti, Apr 2, 2012] The remaining one for ALIP is useful to have an image for it, but not part of the enablement covered by this bp. This will happen at 12.04 once we officially switch to precise.

Meta:
Headline: User of the live-build image creation tool can now create armhf based images which runs on native arm or cross on an intel machine.
Acceptance: Images are successfully being generated and boot correctly.

Work items:
prototype : DONE
refresh live-build sources: DONE
create seeds for precise: DONE
upload linaro-meta precise/armhf: DONE
add armhf support: DONE
generate native test build for nano: DONE
generate cross test build for nano: DONE
generate native test build for developer: DONE
generate cross test build for developer: DONE
generate native test build for ALIP: DONE
generate cross test build for ALIP: TODO
generate native test build for desktop: DONE
generate cross test build for desktop: DONE
nano image test boots: DONE
developer image test boots: DONE
alip image test boots: POSTPONED
desktop image test boots : DONE