v0.4.0

Support for mix firmware.push has been removed. We're all very sorry for this,
but it appears to be unfixable. It was implemented using Erlang's built-in ssh
client which doesn't know about things like the ssh-agent or the .ssh/config
and can't ask for passwords. It also isn't possible to call the system's ssh
since Erlang runs setsid on child processes so they don't have a tty.

The workaround is to run mix firmware.gen.script and then run ./upload.sh.

• Bug fixes
  • Fix exit code parsing from fwup so that errors can be propogated over ssh
  • Disabled the Erlang shell and remote command execution on the firmware
    update port