Handle TestContext class to interface conversion from Spring 3 to Spring 4

Use reflection to make calls to the provided TestContext in StepScopeTestExecutionListener
Enables usage of Spring 4 w/ Batch 2.2 (in this case)
Added Serializable check so exception handling is consistent across 2.2.x and 3.0
Allow multiple configs (xmls, java-files, packages) to be loaded in
ApplicationContextFactory
Added tests to address more situations as well as cleaned up logic a bit
BATCH-2235: Updated ExitStatus#isRunning logic to use correct strings
BATCH-2206: Added option to set collection for MongoItemReader