WIP: Initial implementation of abstract class.

Separated out the Ginga implementation.

Re-organized and updated tests.

Author: pllim

.readthedocs.yml

@@ -16,6 +16,7 @@ python:
       path: .
       extra_requirements:
         - docs
+        - ginga
 
 # Don't build any extra formats
 formats: []

README.rst

@@ -14,7 +14,7 @@ Widgets for the Jupyter notebook and JupyterLab
     :alt: Documentation Status
 
 ``astrowidgets`` aims to be a set of astronomy widgets for Jupyter Lab or Notebook,
-leveraging the Astropy ecosystem. The ``ImageWidget`` implements the API documented at
+leveraging the Astropy ecosystem. The ``BaseImageWidget`` implements the API documented at
 `https://github.com/eteq/nb-astroimage-api <https://github.com/eteq/nb-astroimage-api>`_
 
 **Warning**