MNT: Remove old manifest files that no longer exist. (#1736)

* MNT: Remove old manifest files that no longer exist.

* MNT: Remove 4DD README

Author: zssherman

MANIFEST.in

@@ -7,11 +7,5 @@ include README.rst
 include LICENSE.txt
 include INSTALL.rst
 include pyart/testing/registry.txt
-include pyart/correct/src/UWASHINGTON_4DD_README
 include pyart/__check_build/README
-include pyart/graph/balance-rgb.txt
-include pyart/graph/chase-spectral-rgb.txt
-include pyart/graph/spectral-extended-rgb.txt
-include versioneer.py
-include pyart/_version.py
 include pyart/testing/data/*