#357 new Rule: Date field set without clone

[Hamlet D'Arcy]

If you take a java.util.Date on the constructor or setter, and you assign it to a field... then it *needs* to be cloned or some other thread/consumer could easily modify it.

Example:
class Foo {
Date x
Foo(Date x) {
this.x = x // violation
this.x = x.clone() // better
}

void setX(Date x) {
this.x = x // violation
this.x = x.clone() // better
}
}