Remove boolean options, and replace with flags

[zozzz]

• dumps -> dumps(obj, options: int, ...)

  • ensure_ascii -> DUMP_ENSURE_ASCII
  • encode_datetime -> DUMP_DATETIME
  • options default: DUMP_DATETIME

• loads -> loads(s, options: int, ...)

  • parse_date -> LOAD_DATETIME, LOAD_DATETIME_STRICT, (maybe LOAD_DATE, LOAD_TIME), option for large millisecond handling
  • options default: LOAD_DATETIME | LOAD_DATE | LOAD_TIME