RE: STArray and MutableArray

[Simon Marlow]

> Why are there separate STArray and MutableArray types, as their
> representation is the same?

Just historical reasons.  It Was Decided at some point that the interface
presented by MutableArray to the outside world should take the form of
STArray and IOArray.  

This stuff should probably be cleaned up.  How about we move all the stuff
in MutableArray that's really to do with ByteArrays (well,
MutableByteArrays) into ByteArray, and nuke MutableArray?

Cheers,
        Simon