Merge from master

Signed-off-by: Adam Stokes <adam.stokes@ubuntu.com>
Merge branch 'master' of github.com:Ubuntu-Solutions-Engineering/cloud-installer

Conflicts:
	cloudinstall/juju/__init__.py
	debian/control
Merge branch 'master' of github.com:Ubuntu-Solutions-Engineering/cloud-installer
call polling state directly

Signed-off-by: Adam Stokes <adam.stokes@ubuntu.com>
Add support for additional constraints in add_machine and deploy

Signed-off-by: Adam Stokes <adam.stokes@ubuntu.com>
filter unallocated better

Signed-off-by: Adam Stokes <adam.stokes@ubuntu.com>
expand constraints option

Signed-off-by: Adam Stokes <adam.stokes@ubuntu.com>
add more validation properties

Signed-off-by: Adam Stokes <adam.stokes@ubuntu.com>
replace utils._run with utils.get_command_output

Signed-off-by: Adam Stokes <adam.stokes@ubuntu.com>
stupid conflict string

Signed-off-by: Adam Stokes <adam.stokes@ubuntu.com>