Add Class level KDocs and author tags

Author: sandjelkovic

kotlin/src/main/kotlin/org/axonframework/extensions/kotlin/CombiningCommandCallback.kt

@@ -27,6 +27,7 @@ import org.axonframework.messaging.MetaData
  * @param [R] the type of result of the command handling
  * @param [C] the type of payload of the command
  * @see CommandCallback
+ * @author Stefan Andjelkovic
  */
 internal class CombiningCommandCallback<C, R>(
     val onError: (commandMessage: CommandMessage<out C>, exception: Throwable, metaData: MetaData) -> Unit,

kotlin/src/test/kotlin/org/axonframework/extensions/kotlin/CombiningCommandCallbackTest.kt

@@ -27,6 +27,11 @@ import java.util.*
 import kotlin.test.Test
 import kotlin.test.fail
 
+/**
+ * Tests [CombiningCommandCallback] to verify that it correctly invokes given callbacks.
+ *
+ * @author Stefan Andjelkovic
+ */
 class CombiningCommandCallbackTest {
     private val command = ExampleCommand("1")
     private val commandMessage: CommandMessage<ExampleCommand> = GenericCommandMessage.asCommandMessage(command)

kotlin/src/test/kotlin/org/axonframework/extensions/kotlin/CommandGatewayExtensionsTest.kt

@@ -27,6 +27,11 @@ import org.axonframework.messaging.MetaData
 import java.util.concurrent.TimeUnit
 import kotlin.test.Test
 
+/**
+ * Tests Command Gateway extensions.
+ *
+ * @author Stefan Andjelkovic
+ */
 class CommandGatewayExtensionsTest {
     private val subjectGateway = mockk<CommandGateway>()
 

kotlin/src/test/kotlin/org/axonframework/extensions/kotlin/QueryGatewayExtensionsTest.kt

@@ -30,6 +30,11 @@ import kotlin.test.Test
 import kotlin.test.assertSame
 import kotlin.test.assertTrue
 
+/**
+ * Tests Query Gateway extensions.
+ *
+ * @author Stefan Andjelkovic
+ */
 class QueryGatewayExtensionsTest {
 
     private val queryName = ExampleQuery::class.qualifiedName.toString()