start foundation of juju api

Signed-off-by: Adam Stokes <adam.stokes@ubuntu.com>
to_append is no longer a defaultdict
fix typo
Don't crash when deploying charms with no relations

...also don't append iterables to to_add :-)
Don't switch UI panes without user intervention
Also include 'down' state in the allocated states
Don't do a double deploy of charms
Merge branch 'master' of github.com:Ubuntu-Solutions-Engineering/cloud-installer