修改log

======
###用法

        $log = \mushroom\component\Log::create(array('path' => '/tmp/data.txt'));
        $log->log('info', 'this is a demo'); 
        
        $log = \mushroom\component\Log::create(array('key' => 'demo', 'redis' => '127.0.0.1:6379'), 'redis');
        $log->log('info', 'this is a demo');

修正错误
1. File 文件  直接以文件名创建目录
2. redis 文件 当db为空时  还会select db

修改文件
1. File  文件  增加追加写功能