Upgrade Flask to 0.11.1

[jeffwidman]

• Upgrade all Flask extensions
• Upgrade to latest Flask 0.11 release
• Bonus: replace Flask-Script with Click

[arikfr]

Is it a "simple" upgrade or there are some backward incompatible behaviors?

[jeffwidman]

Most of it should be fairly straightforward. The tricky part is redash is currently using older versions of several Flask extensions, so those may need to be upgraded as well, I'm not sure.

There are a couple of niceties:

• Allowing arrays again in top-level JSON: Add support for serializing top-level arrays to JSON pallets/flask#1671
• Switching to a Click-based integration. You can continue to use Flask-Script, but Click (currently) seems to be the long-term way forward.

[arikfr]

I've updated the issue description with the steps (upgrade extensions -> upgrade Flask -> replace Flask-Script).

[jeffwidman]

Hooray! Thanks @washort!