small refactoring

git-svn-id: svn://svn.forge.objectweb.org/svnroot/spagobi/V_4.x/Server/trunk@20092 99afaf0d-6903-0410-885a-c66a8bbb5f81
now the reader is able to manage also xls file with empty cells

git-svn-id: svn://svn.forge.objectweb.org/svnroot/spagobi/V_4.x/Server/trunk@20093 99afaf0d-6903-0410-885a-c66a8bbb5f81
fixed a syntax error in CREATE TABLE  SBI_EXT_ROLES_CATEGORY


git-svn-id: svn://svn.forge.objectweb.org/svnroot/spagobi/V_4.x/Server/trunk@20094 99afaf0d-6903-0410-885a-c66a8bbb5f81