Warnings when dangerous SQL is generated

[rabbiveesh]

I'm fine with a warning, but it should probably only print once per process? Or maybe once per Translator instance?

Maybe a new setting warn_unimplemented, with values once (default), each, or 0?

Somewhat related, in my local wrapper object I prevent all DROP statements universally, replacing them with a SQL comment and a warning, just to make sure I never deploy a production disaster. It might be nice to make that into a standard feature that all producers are aware of.

Originally posted by @nrdvana in #161 (comment)