Rules and specialisations

[Don Stewart]

I'm keen to work on them. This weekend is open, so will try to get to
them then. I don't think they should be blockers for the release, but
any patches should be ok to merge back into the stable branch when done.

simonpj:
> Hi Don
> 
> You generously offered to deal with these bugs.  I know you are busy,
> but do you think you could spare a moment to say for each (or all!)
> when you might get to them?
> 
> Unless you can't do them after all, in which case by all means say.
> 
> Many thanks
> 
> Simon
> 
> 1434    Slow conversion from Double to Int
> 2269    Word type to Double or Float conversions are slower than Int conversions
> 2270    gcd is specialised only for Int
> 2271    floor, ceiling, round :: Double -> Int are awesomely slow
> 
>