Fix bug delay in notify

Merge pull request #10 from noblakit01/fixbug_notify_delay

Fixbug notify delay

Add support function to get image from cache by url

1.2.1

Add function get image cache by url

Swift 4.0 Support

Merge pull request #9 from noblakit01/swift_4

Swift 4

Fix bug when set url

Merge pull request #8 from noblakit01/fixbug_set_url

:bug: Fix bug set url more than 1 times never callback