Remove -Wall in Haskell mode.
Remove -Wall in Haskell mode.

I've had several reports now that it's annoying to see all those warnings,
particularly for stuff like trivial defaulting for numeric types.  I'm open
to enabling certain specific warnings, but it's clear that -Wall is too
big a hammer.

google/codeworld,alphalambda/codeworld,alphalambda/codeworld,google/codeworld,alphalambda/codeworld,google/codeworld