Refactored RegionFactoryBean and ParsingUtils classes to simplify the code.  Specifically, simplified the logic in the parseExpiration and parseCustomExpiration methods while preserving functional behavior.
Added specific Spring Converter implementations for GemFire RegionShortcut and ClientRegionShortcut enumerated value classes.
Implements SGF-88 - Region Shortcuts; Implements SGF-257 - Strict types in the SDG XSD for Region data-policy and shortcut attributes; Fixes SGF-258 - missing data-policy attribute for Partitioned Regions; Fixes SGF-263 - ineffective application of disk-synchronous attribute setting on Region bean definitions defined with SDG XML namespace.