Fix animals appearing as babies instead of parent

src/main/java/us/myles/ViaVersion/metadata/MetadataRewriter.java

@@ -86,7 +86,10 @@ public class MetadataRewriter {
                             PacketUtil.writeString((String) value, output);
                             break;
                         case Boolean:
-                            output.writeBoolean(((Byte) value).byteValue() != 0);
+                        	if(metaIndex == MetaIndex.AGEABLE_AGE)
+                        		output.writeBoolean(((Byte) value).byteValue() < 0);
+                        	else
+                        		output.writeBoolean(((Byte) value).byteValue() != 0);
                             break;
                         case Slot:
                             PacketUtil.writeItem(value, output);