Added some function

[yusenhan]

https://github.com/yusenhan/Smooth-Line-View I add some function:

1. undo
2. redo
3. clear
4. eraser
5. change color
6. save image to file
7. save image to album

[pixelbitapps]

Hi @yusenhan,

I loved these changes. Could you work out how they could be implemented into the new version where some memory leaks have been fixed?

I've tried to copy them across (the drawStep implementations I mean) but there are multiple design issues (you'll see if you try to do so).

Thanks,

James

[abrar006]

I need these functionalities in https://github.com/levinunnink/Smooth-Line-View...