strict error check on vector manipulation
argc should be int
passing array with a pair of int and pic_value *
adjustment. amending for argc type change
int and size_t
move stack overflow checker
resolve VM's varaible shadows
starndard style initializer
more fix on misc functions in vm.c
explicit int to size_t cast
use ptrdiff to extend exception handler stack
int to size_t conversion
pair functions must use size_t for index, not int
refine description of pic_get_args
add 'k' specifier to pic_get_args format
use k format specifier in blob.c
use k format specifier in vector.c
use k format specifier in pair.c
use k format specifier in string.c
add pic_size_value