Sarpy

Added
Adds CPHDTypeReader and CRSDTypeReader abstract class definitions for better
inheritance structure.

Changed
- Moves CRSD implementation from sarpy.io.phase_history to new subpackage
sarpy.io.received for conceptual clarity.
- Replaces the bad slice convention parsing from the __call__ method with
the standard expected for Python

Added
- Adds and AbstractReader class definition for better inheritance structure.
- Adds SICDTypeReader and SIDDTypeReader abstract class definitions for better
inheritance structure.

Changed
Remap methods changed from flat functions to callable class implementation, for
more clear preservation of remap function state variables

Fixed
Bug fix for file reader `fileno` property usage

Added
Introduces RGIQE methods with sicd degradation functions and a method for
producing a sicd/reader with reweighting and/or subaperture processing applied

Changed
- Adjustments of unit tests to skip versus fail missing tests for CPD validation.
- Refactors some elements of SICD window population to use the
sarpy.processing.sicd.windows module.

Removed
Drops stated support for Python 2.7

Changed
Includes population of North in SIDD exploitation features construction

Fixed
Fixes deprecated numpy.object type usage

Fixed
- Bug fix for default sicd conversion naming scheme.
- Bug fix for Capella SLC symmetry orientation.

Added
Creates command-line utility for SICD chip production

Changed
Unified NITF header field value preservation in sicd and sidd reader, writer,
and conversion