relax SVN archive

Fixes for the write() function.

The display() function now works (although not fully).

Removed the import of the now non-existant Sequence class.

Converted the load_PDB_sequence() class method to a module function.

Converted the write() class method to a module function.

Converted the diplay() class method to a module function.

Removed the now useless methods of the generic_fns.sequence.Sequence class.

Updated all the system tests to use the new relax design!

Updated the copyright notice.

Updated the system test of loading a sequence from a PDB file to use the new relax design.