parse-from-file facility
add built-in library
support exact integer
[bugfix] support 'I' format in pic_get_args
add exact/inexact function
bugfix in pic_get_args
insert type checks in pic_get_args
read line comments
add pic_apply function (and remove pic_run)
[vm] take care of int overflow
the executable binary takes a scheme file to execute in cmd arg line
add tak function benchmark file
create picrin objects in parser stage, not in scan stage
remove stuff rerated to parser_control from scan.l