relax SVN archive

Bug fix for bug #5559.

The idea for the __getattr__ function to generate the non-standard diffusion tensor parameters on
the fly comes from the changes made by Chris MacRaild (c.a.macraild at leeds.ac.uk) in trying to
fix bug #5501 located at https://gna.org/bugs/?func=detailitem&item_id=5501.

The bug can be found at https://gna.org/bugs/?func=detailitem&item_id=5559.

Firstly the Da parameter in the relax test suite is now set to reasonable values.

A special dictionary type class for the diffusion tensor data has been created and is called
DiffTensorData and inherits functions from the base class SpecificData. The 'add_item' function has
been replaced so that the element added is now DiffTensorElement().

The DiffTensorElement data container has been created and inherits its functions from the base class
Element. The __getattr__ function has been added to pick up any references to non-existent
structures. If the name asked for is one of Diso, Da, Dper, Dpar, Dratio, Dx, Dy, or Dz, then the
values of these parameters are calculated for the parameters set in this DiffTensorElement
container. Recursion is used when the equations to calculate the value contains one of the other
non-standard parameters.

The relax test suite element 'Test of the user function diffusion_tensor.display()' now passes.

Creation of a branch for fixing bug number 5559.

The bug report is located at https://gna.org/bugs/index.php?func=detailitem&item_id=5559

Editing of the entire development chapter of the manual.

A few changes to the open source infrastructure chapter.

Spell check of the two manual chapters.

Renamed the file of the open source infrastructure chapter.

Wrote the 'Variable, function, and class names' subsection of the development chapter of the manual.

All the new lines from the end of the 'exampleenv' environments in the manual have been removed.

Major changes to the development chapter of the manual.

The relax-announce mailing list is now included in the intro.

All sections have been significantly edited.

An empty subsection called 'Variable, function, and class names' has been added.

The section 'Committing conventions' has been added and the subsection 'Format of the commit logs'
has been written.

The 'Making changes' section has been added and consists of two subsections, 'Patching' which came
from the start of the chapter and 'Becoming a committer' which describes what is needed to become a
committer.

Major changes to the 'web' manual chapter including a name change to 'Open source infrastructure'.

All sections have been heavily edited.

The 'Downloads' section has been renamed to 'The relax distribution archives' and has been
significantly extended.