metomi/rose#618: start separating array valuewidget into package
metomi/rose#618: split array/entry.py file and debug
metomi/rose#918: implement python list type
Merge pull request #839 from benfitzpatrick/618.new-list-metadata-type

Configuration metadata: add new list type

The new type supports literal representation of lists in Python, JS, Perl, etc. Close #618.