Fix parsing and printing of Bot for effect and closures.

[benl]

In the parser demo interface file we have:

foreign import pReturn
        :: forall t0 t1 %r0
        .  t0 -> Parser %r0 !Bot $c0 t1 t0
        :- $c0        = x : t0

That !Bot won't parse

Perhaps change it to !None

Don't use !_, that's an effect wildcard.

[benl]

Also for types

With the following program:

data IntFun %r1 %r2 %r3 %r4 !e1 $c1
	= FInt (Int %r1)
	| FFun (Int %r2 -(!e1 $c1)> Int %r3)

copyIntFun xx
 = case xx of 
	FInt i	-> FInt (i + 0)

We get:

foreign import copyIntFun
        :: forall %r0 %r1 %r2 %r3 %r4 %r5 %r6 %r7 !e0 $c0
        .  IntFun %r0 %r1 %r2 %r3 !e0 $c0 
                   -(!e1)> IntFun %r4 %r5 %r6 %r7 !_ $_
        :- !e1        = Base.!Read %r0

Note !_ and $_ terms in return type.