OPEN - issue BATCH-339: ItemStream.mark() and reset() should throw a checked exception

http://jira.springframework.org/browse/BATCH-339

Introduce MrakFailedException and ResetFailedException (unchecked for now).  ResetFailedException has to be dealt with specially in the StepExecutor.

spring-batch-core/src/test/java/org/springframework/batch/core/domain/StepInstanceTests.java

@@ -17,8 +17,6 @@ package org.springframework.batch.core.domain;
 
 import junit.framework.TestCase;
 
-import org.springframework.batch.item.ExecutionAttributes;
-
 /**
  * @author Dave Syer
  *