29.11.2017 - GDML_3_1_6
-----------------------

- Updated GDML schema:
  o Extended description for TwistedTubs, to handle all possible configurations
    for the shape, included asymmetric ones.
- Updated documentation accordingly (GDML Guide v.2.7).

22.06.2017 - GDML_3_1_5
-----------------------

- Updated GDML schema:
  o Fix for replicas along angular axis.
  o Added general optical surface properties block.

02.06.2016 - GDML_3_1_4
-----------------------

- Updated GDML schema:
  o Added support for scaled shapes along Cartesian axes.
    Added 'scaledSolid' tag for scale component with values greater than zero.
- Updated documentation accordingly (GDML Guide v.2.6).

09.10.2015 - GDML_3_1_3
-----------------------

- Updated GDML schema:
  o Added support for specifying copy-numbers associated to
    normal volume placements.

12.06.2015 - GDML_3_1_2
-----------------------

- Updated GDML schema:
  o Added optional 'userinfo' tag to allow for 'global' auxiliary fields.
  o Extended auxiliary field with optional 'auxunit' and pointer to
    recursive auxiliary fields (no limit on the number of levels).
- Updated documentation accordingly (GDML Guide v.2.5).

18.11.2014 - GDML_3_1_1
-----------------------

- Updated GDML schema:
  o Corrected MultiUnion structure specification.
- Updated documentation accordingly (GDML Guide v.2.4).

26.11.2013 - GDML_3_1_0
-----------------------

- Updated GDML schema:
  o Added MultiUnion structure and 'generic' Polycone and Polyhedra;
  o Added parameterisation for Ellipsoid;
  o Added parameterisation of Polycone and Polyhedra.
- Updated documentation accordingly (GDML Guide v.2.3).

27.9.2011 - GDML_3_0_1
----------------------

- Updated GDML schema:
  o included ionisation potential (mean excitation energy) property
    to materials.

19.12.2008 - GDML_3_0_0
-----------------------

- Updated GDML schema:
  o included descriptions (with units specification) for parameterised volume
    types: box, tubs, cons, trd, trap, para, sphere, orb, torus, hype.
  o Added elliptical cone shape.
  o Added handling of variables in loops.
- Removed obsolete I/O modules and related configuration/build setup.
  The Geant4 Toolkit now integrated reader and writer with full capabilities
  and making use of the XercesC DOM parser.
