It would be nice to put PackageDictionary ahead of other dictionaries, even
though it's still mutable.  So, we need a separate way of determining the
dictionary into which new symbols go.

    i1 : loadPackage Normaliz
    stdio:1:1:(1):[0]: error: no method found for applying loadPackage to:
	 argument   :  Normaliz (of class Symbol)

    i2 : loadPackage "Normaliz"
    --warning: symbol 'Normaliz' in PackageDictionary is shadowed by a symbol in User#"private dictionary"
    --  use the synonym Package$Normaliz

    o2 = Normaliz

    o2 : Package
