refactor the Ajax request part of server_status_monitor.php
1. split long code to function
2. move functions to server_status_monitor.lib.php
Merge branch 'master' of https://github.com/phpmyadmin/phpmyadmin into 0609_monitor
1. using a better function name 2. fix code style issue 3. add doc for functions
Merge pull request #431 from xmujay/0609_monitor

refactor the Ajax request part of server_status_monitor.php