proposal: add 'unsafeCoerce'

[Ashley Yakeley]

kahl at cas.mcmaster.ca wrote:
> I'd much prefer Data.Unsafe.

I'd like to see all unsafe function in an Unsafe.* hierarchy (possibly 
consisting only of the single module Unsafe). Thus one could avoid 
unsafety altogether by avoiding the Unsafe and Foreign hierarchies.

Otherwise unsafeCoerce should go with all the other unsafe functions in 
System.IO.Unsafe.

-- 
Ashley Yakeley