Remove compat.php

As we now require php >= 5.3, sys_get_temp_dir, json_encode,
json_decode and DateTime are always there.
Move glob_recursive to class.AJXP_Utils.php (only user)

Signed-off-by: Etienne CHAMPETIER <etienne.champetier@fiducial.net>
Merge pull request #340 from echampet/compat.php

Remove compat.php