Altering "varargs" (remove|retain)AllKeys in Jaggregate

As with the analogous jaggregate.Collection methods, I've modified the removeAllKeys( K... ) and retainAllKeys( K... ) methods to have parameter list ( K[] ), and added overloads that have parameter list ( K, K... ), to avoid big confusion when programs hand zero args to the varargs versions of the method. This and the previous modifications will show up in version 2.

Written on January 24, 2006