nicer debugging output with jUnit's ComparisonFailure

FEST currently uses ComparisonFailure when doing isEqualTo with Strings. ComparisonFailure has some extra benefits in modern IDEs, e.g. Eclipse offers extra pop-up info with detailed comparison highlighting the differences.

I propose to use this exception for isEqualTo on other types as well. It could work like this:

1. assertThat(foo).isEqualTo(foo2);
2. if the assertion fails
   1. if the foo.toString() is not equal to foo2.toString() then throw new ComparisonFailure(foo.toString(), foo2.toString())
   2. if the foo.toString() is equal to foo2.toString() then DON'T throw ComparisonFailure because it is confusing
3. assertion doesn't fail. Good for you.

This is a proposal and if you guys think it is useful the please stick it into November release. I think it is useful because on the occasion I remember I temporarily refactored assertions into assertEquals(expected.toString(), actual.toString()) just to have nicer message