---------------------
	Clear up infelicities
	---------------------
	CorePrep, CoreUtils, SimplUtils
	LiberateCase (wibbles only)

* Previously CorePrep was floating LocalIds to top level, which
  breaks the invariant that after CorePrep all top level Ids are
  GlobalIds.  But it didn't really need to, and this pass makes it
  so.  It's much tidier now.

* Make CorePrep do eta expansion on partial applications
	x = foldr f y  ==>   x = \ys -> foldr f y ys
  (This used to be done in the simplifier, but now the
  simplifier only eta expands where there is at least one
  lambda already.)

* Omit CoreUtils.etaReduce.  (Never called.)

* Improve CoreUtils.etaExpand, so that it doesn't add gratuitous
  beta redexes.