Include Python/Groovy version info in the Web UI

[jmao-denver]

As a user, I want to quickly find out what Python/Goovy version my console is running in so that it makes it easier for me to debug potential problems caused by incompatibility between versions.

[mattrunyon]

@devinrsmith I think this will need a bit of server work to expose the Python/Groovy version to the client

[devinrsmith]

I think the groovy bit would be relatively easy, given our current method that looks at jar versions. Python will take a bit of a different approach I suspect, but shouldn't be too much of a lift.

[devinrsmith]

The server side is now publishing groovy.version (and python.version when there is a python script session). Note that groovy.version is still published when running a python script session since it's still technically on the classpath.