Use buildroot to patch buildroot

This makes the patching process more robust. Errors weren't being
caught before.
raspberrypi: add note about controlling terminal
elixir: bump to version 0.13.0
mmccopy: add sudo-mmccopy script

This addresses the problem of it not being easy to run mmccopy under
sudo.
elixir: bump to version v0.13.1
Update make xxx-menuconfig targets to update real config file

I just learned of the Buildroot targets to do this. This saves a
manual copy step.
Use Linaro 2014.01 on bbb since 2014.02 is broke

Something is broke with 2014.02 since it no creates a bootable image.
It's not clear what the problem is, so don't use it for now.
erlinit: bump version to v0.2.1

This fixes a crash when specifying arguments to erlinit via the Linux
kernel command line.
Add note to rebuild after change a br config

Not rebuilding buildroot after a change seems to be one of the top
issues. Hopefully this will help people.