[vector] Mask/Shuffle from/intoArray

[Paul Sandoz]

Hi,

http://cr.openjdk.java.net/~psandoz/panama/mask-to-from-array/webrev/ <http://cr.openjdk.java.net/~psandoz/panama/mask-to-from-array/webrev/>

Methods have been added to create Mask or Shuffle from an array at a index, and likewise store values into an array at an index. 

I kept the Mask/Shuffle.toArray array returning methods. For consistency I added a *Vector.toArray.

I tried to improve the names and consistency of the existing Species factory methods:

  constantMask -> maskFromValues
  trueMask -> maskAllTrue
  falseMask -> maskAllFalse
  constantShuffle -> shuffleFromValues

Paul.