Galaxy can't handle services with multiple ports

[jbardin]

from registry/registry.go:

//FIXME: We're using the first found port and assuming it's tcp.
//How should we handle a service that exposes multiple ports
//as well as tcp vs udp ports

[jbardin]

The listening port is also controlled by the single config variable GALAXY_PORT, which is what is mapped to the first port listed by docker

[jbardin]

The ports definitions are stored in a map, and therefor have no order defined. A service with multiple ports will have it's backend redefined randomly every time commander checks its registration.

[jbardin]

Partially fixed by pull #227. Services still can't expose multiple ports through shuttle, but they will at least be able to work at all.

Services can set GALAXY_PORT to match the internal port assignment that they wish to expose in shuttle.