Added API to store/retrieve Transaction-local key-value pairs.
  * The implementation of the Transaction-local context in
    FenixAbstractTransaction now lazy-loads the map backing the context.
Bug Fix: The DomainPostProcessor will now attempt to find the .class file from its parent.
  * This commit attempts to fix #79.
Refactor CodeGenerator to facilitate the addition of backend-jvstm-common
Add backend-jvstm-common

  * This backend contains code that is common to JVSTM-based backends
  * Some refactorings in CodeGenerator
  * Since a VBox in FF holds the owner and the slotName, remove that duplicate
    information from method's parameters.
  * Add API for generic key-value storage support
  * Add common JVSTMBackend manager
DRAFT: add backend jvstm-infinispan

  * Adjust pom dependencies to consider backend-jvstm-common
  * Update the code generation