relax SVN archive

Created the bmrb_write_software() function for dumping the software info into the BMRB file.

All attributes (even those of None) are being stored.

Import fix from the previous module deletion.

Removed the kludgy bmrb_saveframes module and shifted the code into exp_info.

Shifted the software() and software_select() functions into their own module, 'generic_fns.exp_info'.

Created the bmrb.software() user function for manually specifying the software used.

Updated the __all__ package lists.

Added the software task to the software containers.

More info is now being placed into the software containers of the experimental info container.

Many fixes to the Element and ContainerList to_xml() methods.

The objects within these are now properly converted to XML with the to_xml() method beign called
if it exists.