relax SVN archive

Updated the relative stereochemistry auto-analysis to use the relax library plotting API.

Fix for the backend of the relax_disp.plot_disp_curves user function.

The lib.plotting.api functions write_xy_data() and write_xy_header() require the format argument.

More import fixes for the new pipe_control.plotting.write_xy() function.

The rdc.corr_plot user function backend now uses the relax library plotting API.

The write_xy_data() and write_xy_header() functions from lib.plotting.api are now uses instead of
the equivalent pipe_control.grace functions which no longer exist.

Fixes for the new pipe_control.plotting.write_xy() function.

This includes missing imports which should have moved from pipe_control.grace, as well as shifting
the axis_setup() function from the pipe_control.grace module into the pipe_control.plotting module.

Updated the pcs.structural_noise user function to use the relax library plotting API.

Shifted the pipe_control.grace.write() function.

This is now the format independent pipe_control.plotting.write_xy() function. The format argument
has been added and this defaults to 'grace'. The grace.write user function has been updated to use
the new backend.

Converted all of the Grace plotting in relax to use the plotting API of the relax library.

Created XY-data functions for the plotting API of the relax library.

These are currently copies of the heads of the lib.plotting.grace functions write_xy_data() and
write_xy_header(). These lib.plotting.api functions (write_xy_data() and write_xy_header()) are set
up to use the grace functions.

Copyright update.