Wrong set for EXTDIR when installing, Fixes #336

Signed-off-by: emanuele <emanuele45@gmail.com>
Updated also Settings.php and Settings_bak.php to /ext instead of lib and aligned Settings_bak.php to Settings.php

Signed-off-by: emanuele <emanuele45@gmail.com>
Merge pull request #339 from emanuele45/master

Install problems