ISPN-2504 - WriteSkew check fails for entries which are inserted first time
ISPN-2928 Fix the JDBC configuration parser not to set the connectionUrl
with the driverClass value
Remove unused ResponseGenerator dependency

This used to be injected in CacheImpl to make sure the ResponseGenerator is properly constructed if needed but this is no longer required since ComponentRegistry already does that.
ISPN-2749 Use StateTransferManager.isStateTransferInProgressForKey(key) whenever possible instead of ad-hoc implementations
ISPN-2609 Infinispan SpringCache throws java.lang.NullPointerException:
Null values are not supported!

Add support for storing null values in and retrieving null values from a
SpringCache. Use solution provided by Roland Csupor as a starting point.

* Introduce NullValueSupportingSpringCacheWrapper which wraps a vanilla
SpringCache and adds support for storing and retrieving null values.
* Make *CacheManagers and *CacheManagerFactoryBean aware of optional
support for null values.