Support Flask!

[pearkes]

As a supported framework. :)

[nightkr]

I don't see any errors personally from Flask hackery, my warnings seem to come from SQLALchemy instead (example).

[jayclassless]

Recommend this issue be closed much like #19 was, unless someone knows something specific in Flask that is breaking prospector/pylint/etc.

[carlio]

Yeah, makes sense - "X is broken" is more useful than a generic "support Y framework";