Migrate a lot of Haskell blocks to use standardFunction.
Migrate a lot of Haskell blocks to use standardFunction.

With this changes, standardFunction works for plain variables as
well, and is used for most simple blocks.

There's still a lot that can be done here.  Some remaining cases where
we use non-standard blocks include:

a) Infix operators
b) Blocks with labels different from generated code (e.g., pi)

This commit partially mitigates #332

stefan-j/codeworld,pranjaltale16/codeworld,google/codeworld,tgdavies/codeworld,pranjaltale16/codeworld,three/codeworld,google/codeworld,alphalambda/codeworld,parvmor/codeworld,alphalambda/codeworld,nomeata/codeworld,tgdavies/codeworld,tgdavies/codeworld,parvmor/codeworld,nomeata/codeworld,nomeata/codeworld,venkat24/codeworld,pranjaltale16/codeworld,stefan-j/codeworld,parvmor/codeworld,stefan-j/codeworld,alphalambda/codeworld,three/codeworld,venkat24/codeworld,venkat24/codeworld,three/codeworld,google/codeworld