Introduced network.PortRange interface.
Modify providers to handle port ranges for environment ports.
Update provider instances to handle port ranges.
Remove debug statements.
Simplified port range overlap checking.
Implemented port collapsing function.
Use CollapsePorts in joyent provider.
Separate state port range definition.
Additional tests for joyent firewall rule construction and parsing.
Added multiple port port ranges to provider live tests.
Additional tests for ec2 provider and style fixes.
Additional tests for openstack provider.
Merge pull request #455 from tasdomas/port-ranges-provider-support

Port ranges provider support

Working on https://bugs.launchpad.net/juju-core/+bug/1337817 - enabling port range support in juju-core. This branch modifies the provider interface and its implementations to handle port ranges. They are silently converted into old-style port slices on the firewaller. Port range support in the firewaller is still in progress.