[evla-sw-discuss] Change

[Barry Clark]

I am going to change the return type for
    Subarray.getAntennas()
>From an Enumeration to a Collection <Antenna>.
I don't really think this affects anybody else, but I thought I ought to
let people know.

I rather suspect that jython implements both Enumerations and Collections
as tuples, but I don't know for sure.

I am also adding 
    Subarray.getAntennaHash()
which returns a Hashtable.  Which might show up in jython as a dictionary.