Added the 'test.seq' file from bug report #20873 (http://gna.org/bugs/?20873).
This is from Troels E. Linnet (http://gna.org/users/tlinnet). The bug report and link to
http://thread.gmane.org/gmane.science.nmr.relax.user/1452 explains the contents.
The file will be used to construct a system test to catch the bug.
