Out of date TTSC link in A.3 in index.html

[<stephen_green@seventhproject.co.uk>]

Should the link to the TTSC for implementations (A.3) not
be updated. It is currently reports that implementation
tools can be found at
http://www.oasis-open.org/committees/tc_home.php?wg_abbrev=ubl-ttsc
but this page says "This web page is no longer in use."

Steve