Add packaging of a .zip file that has Windows line-endings, and remove the packaging of a .tar.gz.
Add packaging of a .zip file that has Windows line-endings, and remove the
packaging of a .tar.gz.

* dist.sh:
  (prepare_directory): new function to do basic preparation and
    verification of the release
  (...): export and package twice. remove .tar.gz packaging.

justinweb/serf,Manouchehri/serf,wzugang/serf,sworda/serf,TommyU/serf,liuzongquan/serf,justinweb/serf,wzugang/serf,liuzongquan/serf,idomon/serf,muthusuba/serf,wzugang/serf,TommyU/serf,idomon/serf,sworda/serf,krime/serf,muthusuba/serf,Manouchehri/serf,sworda/serf,Manouchehri/serf,sworda/serf,blueszhangsh/serf,idomon/serf,blueszhangsh/serf,krime/serf,blueszhangsh/serf,krime/serf,Manouchehri/serf,muthusuba/serf,muthusuba/serf,TommyU/serf,liuzongquan/serf,krime/serf,justinweb/serf,blueszhangsh/serf,TommyU/serf,justinweb/serf,idomon/serf,wzugang/serf,liuzongquan/serf