### delete
删除表中的数据
delete($table, $where)
* ##### table [string]
表名.
* ##### where [array]
WHERE 删除条件.
Return: [number] 返回被删除的行数.
一个比较危险的操作，操作前请考虑好。。。
~~~
$database->delete("account", [
"AND" => [
"type" => "business"
"age[<]" => 18
]
]);
~~~
