[jvstm-common] Implementing Long Lived Transactions
[jvstm-common] Added a method to JVSTMDomainObject to return a VBox by its name

  * Also uniformized the format of the generated code for JSON handling
[jvstm-common] Proper support for Transactional Context commit
Optimizations...
[long-tx-api] Caching DomainSlotKey's hashCode
[jvstm-common] Only validate Long Lived Transaction if anything was written
[long-tx-api] Refactor: Read/WriteSet is now kept as a ValueType