renamed comparator() to comparer()
aborted attempt to make the Comparator classes static (called
Equivalence). It doesn't work because I can't declare the type of the
additional variable that must be passed to compare(), now called
equalTo(). This commit has Equivalence be generic
I think I solve the problem...declare the additional argument as Domain,
then cast it inside each areEqual to the enclosing class type
made AbstractDomainEquivalence an extension of guava's Equivalence;
noted that the interface DomainEquivalence is probably useless.
Indeed, guava doesn't have an Equivalence interface, and the
implementation classes of DomainEquivalence extend
AbstractDomainEquivalence so that there are currently no references to
the interface DomainEquivalence
eliminated the interface DomainEquivalence after removing all
references to it (DomainEquivalence now looks like guava Equivalence)
renamed to isEqual
split AbstractDomainEquivalence into the guava Equivalence portion,
called DomainEquivalence, and AbstractDomainAreEqualTester.
renamed AbstractDomainEqualityMultiTester into
AbstractDomainIsEqualTester
renamed the Domain compare() and equalTo() methods to 
isEqual_Is() and isEqual_Are() to remark that they are both defined for
one arguement but based on the IsEqual are AreEqual implementations
respectively
narrowed the private Tester declarations; made embedded classes private;
unfortunately areEqualTester() and isEqualTester() must be public, they
appear in the AbstractDomain interface, can't this be avoided?
introduced a new strategy for equality testing. All the testing code is
now in the class DomainEqualityTesters, which is some sort of visitor
minor changes (mostly comments) after pondering after the inverted order
d1,d2 between the Visitor approach and nested class delegate approach;
renamed accept by adding a Visitor tag
DomainEqualityTesters stores an object onArrayList, otherwise a new one
is created at each forOnArrayList() call
removed the nested visitor definition, using the one in
DomainEqualityTesters