Proposal: merge either into transformers

[Herbert Valerio Riedel]

Roman Cheplyaka <roma at ro-che.info> writes:

> I propose to add the sole module of the 'either' package[1],
> Control.Monad.Trans.Either, to the transformers package.

+1


[...]

> Note that 'either' depends on the 'semigroupoids' and 'semigroup'

btw, the package is named 'semigroup*s*'