[dml] Added the concept of version to Project
[core-api] New Feature: Store information about the installed modules

  * Upon initialization, information about the installed modules is kept
    in an instance of InstallationData
  * In the future, this information will be usable to perform automatic
    store upgrades
[core-api] Make ModuleData and ModuleInstallation Serializable

  * Some backends are still breaking the contract and require ValueType
    classes to be Serializable
New Feature: Added public API to verify if a DomainObject is valid
[jvstm-ojb] When deleting an object, put a "Deleted" mark on its VBoxes
[dml-compiler] New Feature: Support modifiers in classes, slots and relation roles

  * For now, only the "public" and "protected" modifiers are supported
[dml-compiler] Allow modifiers to control the visibility of generated methods and classes

  * For now, only the visibility of classes, slots and roles is affected
  * The default behaviour (if no modifier is specified) is public.
  * If the "protected" modifier is specified, the generated method will be protected
Merge pull request #185 from jcarvalho/feature/slot-visibility

Allow control of slot/role visibility
[DSI Releaser] prepare release v2.4.0
Merge branch 'release/2.4.0' into develop
[DSI Releaser] prepare for next development iteration
[dml-compiler] Minor Change: Add @SuppressWarnings to generated classes
Updated ASM to version 5.0, allowing fenix-framework projects to compile on Java 8

  * Closes #188
[jvstm-ojb] Bug Fix: RelationList now properly extends AbstractSet
Added Neo4j Backend