update python mem to 512mb again

merge with java-branch and also move grader-process-check to SAMPLE

merge algo-bm

merge

merge with master

upgrade to python3

consolidate with the master

backport

update install script

merge fix utf8

accommodate mem limit in php and java, using new box64

add option -A <opt> to box. This options allow more argument to be explicitly passed to the program We have to use this because if the argument we wish to pass to the program is option (in -? format), box will intepret it as its option and failed accordingly. be noted that, by the definition of getopt, these options will be put after original argument (check the code for more info)

use redirection by system(, {out: , err: }) instead of by > or 2> in the command

fix bug

add more logging

update run

fix run of php

change runtime checking for php,ruby,python

add -s clone to run php

merge