Change mrb_get_args() parameter "argc" type to mrb_int because mrb_get_args() requires mrb_int.
change sqlite3_bind_int to sqlite3_bind_int64 because value > INT_MAX overflows.
Merge pull request #8 from yasuyuki/int64

Change mrb_get_args() parameter "argc" type to mrb_int because mrb_get_a...