request #7204: links in readme are outdated

 * tuleap.com ---> tuleap.org
 * Link of new tuleap developer guide

Change-Id: Ia671698c3f763671c1938f1c1df85136c030c1fc
Merge commit 'refs/changes/05/2705/2' of ssh://gerrit.tuleap.net:29418/tuleap into stable

* ssh://gerrit.tuleap.net:29418/tuleap:
  request #7204: links in readme are outdated
This is Tuleap 7.2.99.39

Change-Id: If14687c63c436ccd46ece8fb8eed966b9e34cdd8