2) The new "Monitor" Link is added into the mainpage/main panel;
3) The xCAT version displayed at the bottom of web page is updated;
4) $TOPDIR variable is added. The reason is that if the file display.php is invoked in one sub-directory, there will be php errors.
git-svn-id: https://svn.code.sf.net/p/xcat/code/xcat-core/trunk@3810 8638fb3e-16cb-4fca-ae20-7b5d299a9bcd
