A single settings dict

[jsocol]

The trend in django core has been to move from lots of NAMESPACE_* settings to NAMESPACE = {'FOO': 1}. I think in the interest of reducing settings namespace bloat, and simplifying some code in a few places (well, replacing getattr() with .get(), mostly), this is a good trend and we should move the WAFFLE_* settings into a WAFFLE dict.

[willkg]

I'm +1 on this.

[jsocol]

Since it's another breaking change, I'm putting it in 0.12 for now.