relax SVN archive

Fixes for the EPS versions of some Oxygen icons used in the relax manual.

This is the actions.document-preview-archive and actions.office-chart-pie Oxygen icons used for the
user function icons. The files were not created correctly in the Gimp. The export to EPS requires
the width and height to be both set to 6 mm, and the X and Y offsets to zero. This allows the icon
bounding boxes and sizes to match the other EPS icons.

Created the empty pipe_control.statistics module.

This will be used for the backend of all of the statistics user functions.

The statistics.model user function now uses the new statistics wizard graphic.

Created a wizard graphic for the statistics user functions.

This is based on a number of Oxygen icons, as labelled in the SVG layer names.

Created the frontend for the statistics.model user function.

Small fix for the structure.add_model user function description.

Created the empty statistics user function class.

This adds the infrastructure for creating the statistics user functions.

Added the office-chart-pie set of Oxygen icons for use in the new statistics user function class.

Added the structure.align user function to the renaming translation table.

This is so relax identifies structure.align user functions in scripts to raise an error saying that
the structure.superimpose user function should be used instead.

Created the N_state_model.test_statistics system test.

This system test will be used to implement the new statistics user function class consisting of the
structure.model and structure.aic user functions for calculating and storing the [chi2, n, k]
parameters and Akaike's Information Criterion statistic respectively.