relax SVN archive

Fixes and improvements for the gnuplot correlation_matrix() plotting API function.

This is for the structure.atomic_fluctuations user function. The "pm3d map" plot type is incorrect
for such data type, so instead of using 'splot', 'plot' is being used instead. The resultant EPS
file is now much smaller. The colour map has also been changed to one of the inbuilt ones for
higher contrast.

Docstring fixes for the Structure.test_atomic_fluctuations_gnuplot system test.

This was pointing to the structure.rmsd user function instead of structure.atomic_fluctuations.

Updated the Structure.test_atomic_fluctuations_gnuplot system test.

This is for the gnuplot correlation_matrix() plotting API changes which affect the
structure.atomic_fluctuations user function.

Improvement in the comments from the gnuplot correlation_matrix() plotting API function.

Significantly expanded the gnuplot script from via the correlation_matrix() plotting API function.

This is for the structure.atomic_fluctuations user function. The output terminal is now set to EPS,
the colour map changed from the default to a blue-red map, labels have been added, the plot is now
square, and comments are now included throughout the script to help a user hand modify it after
creation.

The gnuplot correlation_matrix() plotting API function now creates a text file of the data.

The lib.plotting.gnuplot.correlation_matrix() function now calls the
lib.plotting.text.correlation_matrix() function prior to creating the gnuplot script.

Fix for the structure.atomic_fluctuations user function backend.

The pipe_control.structure.main.atomic_fluctuations() function no longer opens the output file.

More simplifications for the structure.atomic_fluctuations user function backend.

Shifted the matrix output of the structure.atomic_fluctuations user function into lib.plotting.text.

The new lib.plotting.text module will be used by the relax library plotting API to output data into
plain text format. The current correlation_matrix() function, which has been added to the API
correlation_matrix() function dictionary, simply has the file writing code of the
structure.atomic_fluctuations user function. This significantly simplifies the user function.

Enabled the gnuplot format for the structure.atomic_fluctuations user function.

This uses the plotting API correlation_matrix() function for visualisation. The change allows the
Structure.test_atomic_fluctuations_gnuplot system test to pass.