Function type naming conventions

[Brian Goetz]

> Why not be plainer about it and use FromIntFunction.
> People will catch on that the other one, IntFunction means ToIntFunction.

Note that IntFunction only means ToIntFunction for SAMs where the return 
is generic.  Otherwise it means FromIntBlock.  The rule we've got now 
specializes type parameters in order, but pretending that the return 
position (if generic) is first.

> Or you could redo that side of the naming pattern as FunctionToInt etc?
> (Although probably not all the way to renaming IntOperator as
> FromIntFunctionToInt...)

I played with that at first, and wasn't thrilled about how it scaled to 
to multiple arguments or non-Function bases:

   BiBlockFromTInt / FromTIntBiBlock

vs the proposed

   TIntBiBlock

which seemed more consistent with what we had so far?