Delayed release

The next BETA release of SimpleDBM has been delayed due to my desire to re-factor some of the code. The re-factoring has been focused on following:

• Removing all singletons - even Loggers. Unfortunately, Log4J and other logging packages all use singletons, so this is not completely possible unless I replace the entire logging package.
• Ensuring that the serialization mechanism uses constructor based object initialization rather than retrieving state after construction.
  
• Above enables the use of final fields in many objects, allowing them to be immutable.
  

All of these changes are designed to increase robustness, and also to ensure that multiple instances of SimpleDBM can co-exist within the same JVM, and even the same Class Loader, without conflict.