Add word-sequence numbering to relex

This is needed so that the order of the words in a sentence can be more easily deduced; used by Hujie forthe GSOC 2014 anaphora resolution project.
Hello Linas,

You seem to have removed something needed by (relex-parse ...) in logic mode here?  I posted about it on https://groups.google.com/forum/#!topic/opencog/3BDCgr-3qpQ

Or should this sequence number change be used by Relex2Logic as well?