Do not apply built-in conversions for source properties that are already assignable to the target

Fixes #328
Oh, right... there was something... ;)

To be honest, I changed that because I stumbled accross that and Sjaak and I just joked a day before about him keeping using equals from time to time.

But there's actually no good reason to use equals to compare enum instances. But there are several good reasons to use ==. First, it's type-safe. The compiler will throw an error if not both sides have the same enum type. Second, it's null-safe. Using equals requires the lhs to be non-null. Either side of == may be null for the check to be performed without throwing exceptions.

Findbugs etc contain rules to suggest using == instead of equals as well.