Enable decode of java.util.ArrayList as vector instead of list

[dcj]

If replacing the current behavior is acceptable, then the change is

java.util.ArrayList
  (decode [data]
    (mapv decode data))

If replacing current behavior isn't acceptable, then provide a way to optionally select this behavior...

[owainlewis]

I made a fork which returns vectors when parsing java.util.ArrayList

https://github.com/owainlewis/yaml