PIVOT-799: Improve operation of Pivot collections objects.

This is just a part of what could be done, according to the issue:
* Add a new constructor to ListAdapter that can take either an Array
  of objects or a variable-length list of objects and convert to
  a Pivot list (using Arrays.asList).  This simplifies using an
  Enum.values() list (for instance) as the basis of Pivot data.


git-svn-id: https://svn.apache.org/repos/asf/pivot/trunk@1588304 13f79535-47bb-0310-9956-ffa450edef68