add bifunctor

common/api/src/main/java/com/dfsek/terra/api/util/generic/data/BiFunctor.java

@@ -0,0 +1,14 @@
+package com.dfsek.terra.api.util.generic.data;
+
+import java.util.function.Function;
+
+
+public interface BiFunctor<T, U, B extends BiFunctor<?, ?, B>> extends Functor<T, B> {
+    @Override
+    default <V> BiFunctor<V, U, B> map(Function<T, V> map) {
+        return mapLeft(map);
+    }
+
+    <V> BiFunctor<V, U, B> mapLeft(Function<T, V> map);
+    <V> BiFunctor<T, V, B> mapRight(Function<U, V> map);
+}