relax SVN archive

This patch includes a large number of changes. The 'grace.write()' user function docstring has been
updated and now includes the previously missing relaxation curve-fitting data type string matching
patterns.

In the module specific_fns.relax_fit the relaxation curve-fitting data type string matching patterns
have been updated to include the 'ave_intensities' series object (an array) and the 'relax_times'
series object. The 'self.return_grace_string()' method has been updated to include axes labels for
these objects. The 'self.return_value()' method of the specific_fns.base_class module has been
modified to check for data in 'self.relax.data' if the spin system specific data does not exist.

The relaxation curve-fitting sample script has been updated to create plots of the minimised
chi-squared value, the initial peak intensity, the relaxation rate, the average peak intensities,
and the normalised average peak intensities.

Plot normalisation is now supported for series-like data through the 'norm' argument to the
'grace.write()' user function. For relaxation curves, all plots will commence at the value of one.
This feature is useful for emphasising errors in the data sets.