relax SVN archive

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.

Implemented a very basic gnuplot backend for the correlation_matrix() plotting API function.

This is in the new lib.plotting.gnuplot module. It creates an incredibly basic gnuplot script for
visualising the correlation matrix, assuming a text file has already been created.

Created the lib.plotting API function correlation_matrix().

This is the lib.plotting.api.correlation_matrix() function. It will be used for the visualisation
of rank-2 correlation matrices. The current basic API design here uses a dictionary of backend
functions (currently empty) for calling the backend.

Created the Structure.test_atomic_fluctuations_gnuplot system test.

This checks the operation of the structure.atomic_fluctuations user function when the output format
is set to 'gnuplot'. This will be used to implement this option. The current gnuplot script
expected by this test is just a very basic starting script for now.

Created the empty lib.plotting package.

This follows from the thread at http://thread.gmane.org/gmane.science.nmr.relax.devel/7444.

The package will be used for assembling all of the data plotting capabilities of relax. It will
make support for different plotting software - Grace, OpenDX, matplotlib, gnuplot, etc - more
coherent. This will be used to create a software independent API for plotting in relax. I.e. the
plotting software is chosen by the user and then the data output by the user function passes into
the lib.plotting API which is then passed into the software dependent backend in lib.plotting.

Implemented the lib.io.swap_extension() function.

This is confirmed to be fully functional by its four unit tests.