incompatibility fix with old basename

Prior to basename v8.20, the -s option didn't exist, and previous
versions used a syntax where the suffix followed the filename instead.
Since this is still supported even on new versions of basename, I
changed the script to allow older versions of basename to work (which
still ships even the latest debian 7.3 for instance).
alix_defconfig: enable large files and wchar

Large files are needed for pretty much everything, so enable them to
avoid fighting issues. wchar is needed for target mtools.
Bump buildroot tag to pull in Erlang 17.0

This also brings various other patches, but nothing that looks
consequential to Nerves configurations.
rpi: switch to external toolchain

This speeds up the build at the cost of a slight increase in image size.
Force build configuration choice; update docs

It was getting to easy to choose the buildroot default. This commit also
adds info about caching downloads which is really important.
rpi: Enable hardware interfaces (gpio, i2c, spi)
erlinit: bump version to v0.2.0
rpi: add erlinit.config to force controlling tty

This is needed to select between seeing the prompt on HDMI vs. seeing
the prompt over the UART.
nerves-env: add erl_interface to the library list
syslinux patch just got accepted into buildroot
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.
Pull in support for fwupdate using external unzip

This significantly reduces firmware programming time. The key changes
are in the nerves-utils project.