setup
add CheckBox widget to viewer.  fix ComboBox widget docstring
added tv_denoise.py viewer example using the CheckBox
fix image scaling in tv_denoise.py example
Clear the blit background when the image changes
Merge pull request #1144 from blink1073/master

Clear the blit background when the image changes
Update find_contours docstring to use r/c notation

This update fixes #1140.

Other docstrings will probably need to be updated as well.
Merge pull request #1145 from jni/find-contours-docstring

Update find_contours docstring to use r/c notation
Fix swirl docstring to use (row, column) nomenclature
Remove extra space
code formatting fixes
Remove blit background when overlay changes
Use functools.wraps in default_fallback dectorator
Merge pull request #1151 from blink1073/default_fallback_doc

Use functools.wraps in default_fallback decorator

Fixes #1149, allowing functions wrapped by `default_fallback` to keep their docstring.
Rename (x, y) -> (row, col) in _geometric.py.
Merge pull request #1146 from blink1073/master

Fix docstrings to be less confusing about pixel coordinates.
Improve desciption of inverse_map and add option to direclty pass coordinates
Improve inverse_map description
Make warp function N-D compatible, and add example to doc string
Remove deprecated parameter of warp