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	More stuff towards generalising 'foreign' declarations
	------------------------------------------------------

This is the second step towards generalising 'foreign' declarations to
handle langauges other than C.  Now I can handle

  foreign import dotnet type T
  foreign import dotnet "void Foo.Baz.f( T )" f :: T -> IO ()



			** WARNING **
	I believe that all the foreign stuff for C should
	work exactly as before, but I have not tested it
	thoroughly.  Sven, Manuel, Marcin: please give it a
	whirl and compare old with new output.


Lots of fiddling around with data types.  The main changes are

* HsDecls.lhs
	The ForeignDecl type and its friends
	Note also the ForeignType constructor to TyClDecl

* ForeignCall.lhs
	Here's where the stuff that survives right through
	compilation lives

* TcForeign.lhs DsForeign.lhs
	Substantial changes driven by the new data types

* Parser.y ParseIface.y RnSource
	Just what you'd expect