relax SVN archive

Redesign of get_data() and deletion of determine_graph_type().

get_data() determines the graph type in a few lines of code, so determine_graph_type() is not
necessary. get_data() now returns the 4D grace graph data structure, the labels for the data sets,
and the graph_type.

Changed the format of the data arg to write_xy_data().

This is a huge simplification and makes the function more usable for any type of data thrown at it.
The structure is now expected to be a 4D list/array corresponding to Gx, Sx, data point, data point
info.

Shifted to using write_xy_data().

This was the write_multi_data() function, and write_data() function has been deleted.

Fix for the counting of the number of graph sets.

Spin ids are no longer passed into write_xy_header().

Instead the new args seq_type and set_names are passed in.

Typo fix in write_xy_header().

axis_label should have been axis_labels!

Added the axis_min and axis_max args to write_xy_header() for specifying the graph ranges.

Fix for the call to write_xy_header().

This is now independent of the number of data sets, and is called correctly.

Deletion of the write_header() function.

This is now redundant due to the improvements in write_xy_header().

Added symbol formatting to the individual graph sets in write_xy_header().