Fixed several typos and a broken internal reference.

git-svn-id: svn://svn.forge.objectweb.org/svnroot/contrail/trunk/conpaas@5045 ef35cc4a-2640-4bbf-98bc-65920db7d8ae
Mention XtreemFS at the end of the tutorial.

git-svn-id: svn://svn.forge.objectweb.org/svnroot/contrail/trunk/conpaas@5046 ef35cc4a-2640-4bbf-98bc-65920db7d8ae
Added documentation about how to set a higher maximal upload file size for the web frontend.

git-svn-id: svn://svn.forge.objectweb.org/svnroot/contrail/trunk/conpaas@5047 ef35cc4a-2640-4bbf-98bc-65920db7d8ae
Introduction and minor modifications

git-svn-id: svn://svn.forge.objectweb.org/svnroot/contrail/trunk/conpaas@5049 ef35cc4a-2640-4bbf-98bc-65920db7d8ae
Modifications in the contribution and minor changes in the rest

git-svn-id: svn://svn.forge.objectweb.org/svnroot/contrail/trunk/conpaas@5052 ef35cc4a-2640-4bbf-98bc-65920db7d8ae