relax SVN archive

Fix for the assignment handling in the lib.software.sparky.read_peak_list() function.

The first element is usually the indirect dimension or w2.

Changed the spectrum.read_intensities dim argument default to w2 and improved the long description.

The lib.software.sparky.read_list_intensity() function now operates on the Peak_list object.

Small fix for how pipe_control.spectrum.read() uses the Peak_list object.

Fix for the lib.spectrum.objects.Peak_list object - the Assignment object was not initialised.

The Peak_list object is now used by the lib.spectrum.peak_list.read_peak_list() function.

The pipe_control.spectrum.read_intensities() function now works with the Peak_list object.

Started to shift the spectrum.read_intensities user function backend to use lib.spectrum.peak_list.

Created the new lib.spectrum.objects module.

This will hold temporary data structures for representing peak lists and other spectral data. The
module currently contains the Peak_list class which is used to hold peak list data.

Replaced the 'heteronuc' and 'proton' arguments of the spectrum.read_intensities user function backend with 'dim'.