Allow the creation of a PDS3Image object from a numpy array

[bvnayak]

Allow save to create a PDS3Image object from a numpy array, which will serialized it out to a PDS3 file.

• Make a label for an array which contains useful information about an image. Such as,
  • Lines
  • Line Samples
  • Bands
  • Sample_Bits
  • Sample_Type
  • ^Image
• Make save function to distinguish between a numpy array and PDS Image with label

[godber]

I think this task might be better stated as "Allow the creation of a PDS3Image object from a numpy array". Which should, in turn, be able to be serialized out to a PDS3 file with the .save() method.

[bvnayak]

Issue updated.