Updated Maven repository URL

  * The old one still works, this doesn't print so many warnings
[core-api] Added utility "withTransaction" methods that are useful for Java 8
[DSI Releaser] prepare release v2.4.1
Merge branch 'release/2.4.1' into develop
[DSI Releaser] prepare for next development iteration
[jvstm-ojb] Removing unused DatabaseDescriptorFactory and SqlTable
[jvstm-ojb] Byte arrays are now stored as MySQL longblobs
[jvstm-ojb] Internal cleanup, formatted source code according to the conventions

  * Also removed some unused classes and internal methods
[jvstm-ojb] DO_State is no longer Serializable

  * DO_States were never serialized, so this should slightly reduce
    compilation times and final application size
Dependency cleanup

  * Remove dependency from Commons Lang
  * JGroups on Core-API is now optional
[dml-compiler] DomainObjectAllocator no longer relies on specially injected constructors