Comparing unrelated types with equals

Ported from scapegoat. Will warn if comparing unrelated types with equals (which will always return false according to contract)
True, didn't think of that, the rule exists in the built in set of warnings in intellij as well. I thought there was clear wording about equals not being allowed to be true for two objects of different class, but when I revisited the javadocs for jdk 7 it doesn't say anything like that.

I think we can just skip this rule instead, it doesn't feel very useful for eq as it is used so seldom (in the Scala codebases I have seen at least.)