BATCH-2005: Implement JSR RetryListener along side Spring Batch's RetryListener
Update schema-derby.sql

Fix JOB_CONFIGURATION_LOCATION field (should be DEFAULT NULL or NOT NULL)
BATCH-2100 Add CONTRIBUTING.md file
* changed keyword from "type" to "engine"
* changed from MyISAM to InnoDB
* fixed property "platform" from "oracle10g" to "mysql"
BATCH-2053: Allow overriding step scope proxy-target-class flag on bean
level with aop:scoped-proxy