- fixed by creating new php file airtime-installed-check, which checks whether current version
of airtime exists; this file gets called right after root user check and whether debian
package exists check
- moved some code from airtime-install.php to AirtimeInstall.php as static functions
so that we reduce duplicated code
- both the new file airtime-installed-check.php and airtime-install.php use the new
static functions created above
Martin Konecny
Yuchen Wang