quickFileWritable()

Signed-off-by: Suki <suki@missallsunday.com>
replace raw @chmod calls with quickFileWritable
on upgrade.php

Signed-off-by: Suki <suki@missallsunday.com>
oops, I got the Call-time pass-by-reference wrong :P

Signed-off-by: Suki <suki@missallsunday.com>
Merge pull request #2442 from MissAllSunday/writable_files

Writable files