added PreventUpdate exception and attached handler to Flask server#190

Merged

chriddyp merged 5 commits intoplotly:masterfrom ned2:add-prevent-update-exception

Jan 19, 2018

+61

Commits on Jan 13, 2018

added PreventUpdate exception and attached handler to Flask server
Ned Letcher
committed
forgot about Python 2

ned2
authored and
Ned Letcher
committed
making flake8 happy

ned2
authored and
Ned Letcher
committed
make pylint happy about supposedly unused variable
Ned Letcher
committed
added integration test
ned2
committed