Next generation steps identified by CHM

[mohawk2]

In an email in Dec 2015, Chris wrote things that could be incorporated in future PDL*:

ArrayFire GPGPU parallel computing:
http://www.arrayfire.com/docs/index.htm
This could give PDLng a quick start for
high performance using GPUs.

COS, the C Object System:
https://github.com/CObjectSystem/COS/blob/master/doc/cos-draft-dls09.pdf
https://github.com/CObjectSystem/COS
This could give PDLng an object oriented
interface that maintains a C FFI so that
PDLng could call or be called from other
languages. Matplotlib anyone?

HDF5 Attributes:
http://www.hdfgroup.org/HDF5/doc1.6/UG/13_Attributes.html
I was thinking that our PDLng implementation
should cover the bases from FITS, HDF5, named
dimensions,.. Ingo has already done some
work along these lines.

[mohawk2]

Closing this to merge it into #349.