The ImmutableCollections class has been added, which takes care of those functions of the
Collections class that do not update the (immutable) collections that the methods receive
as arguments.
Cat class in the logger package belongs in dsol, not in djutils, so removed it.
The 'decoderdumper' package has been added to the djutils project, extending
and replacing HexDump.
The CategoryLogger has been extended with a 'when(condition)' static method.
A call like CategoryLogger.when(ok).always().info("Ok"); is now possible.
The HexDump class has been added to djutils to create hexadecimal dumps of data.
Copyright message changed to 2019.
The 'means' package has been added to the djutils project.
Several classes from other projects that are heavily shared between the projects, but not
specific for one of the projects have been transferred to the djutils project.