void token::create( account_name issuer,
asset maximum_supply,
uint8_t issuer_can_freeze,
uint8_t issuer_can_recall,
uint8_t issuer_can_whitelist )
void token::issue( account_name to, asset quantity, string memo )
36.4.3. token::transfer 转账方法
void token::transfer( account_name from,
account_name to,
asset quantity,
string memo )