relax SVN archive

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.

Expanded the experimental information data container to include all the software info.

The bmrb.software_select() user function is now more functional.

Modified the system test to force save the program state.

Created the ContainerList base class object.

This is just a generic list type with XML methods, used to hold basic elements.

Created the user function bmrb.software_select().

This currently doesn't do anything.

Created a data container for storing experimental details.

This will be used extensively for the BMRB file generation.

The program state is now being saved in the BMRB system test.

Comment fix.

The SVN repository URL is now sent into the Software saveframe.