Add mouse actions for scrolling

[emassey0135]

This adds actions for scrolling up and down by 1 line or 1 pixel. This is a very common mouse action, and among other things, this can be used to cycle through the hotbar in Minecraft, or to make things visible on screen that were hidden before.

[MicahKimel]

This is awesome, I was also thinking about adding this feature for a project I recently started!

My only question is there are already commands for moving the mouse and such, so why not instead of capture mouse location with your new command you could capture how many pixels the user would like to scroll.

For example cliclick su:100 to scroll up 100 pixels or cliclick sd:100 to scroll down 100 pixels.

I feel like doing it this way would add a lot more value to the project than only scrolling 1 pixel at a time. Let me know what you think!