add support to create sshable image

fix Dockerfile for Centos
fix DockerHostSshDriver.createSshableImage effector
fix some errors due to latest Brooklyn changes
work for DockerHostLiveTest
removing MachineLocation interface from DockerHostLocation
Update to wrap a JcloudsSshMachineLocation container
Fix compile errors
Addiung SubnetTier and PortForwarder to the DockerHost entity
Add logging configuration
Fix startup of SubnetTier
Tidying
Fix build errors and tidy up methods
Introduce symmetry ion start and stop methods
Fix container startup and dockerfile creation
Imports and LOG field
Remove driver for container and set SERVICE_UP when SSHable
Fix attributes
Better error checking when creating dockerfile image
Add iptables and security group configuration
Set the container image ID based on dockerfile uploaded
Add more sensor definitions and renderer hints
Return ther full image ID from the buildImage command
Improvements to buildImage and better Javadoc comments
Add flags for Docker loginUser