Complete overhaul (Add functionality, typing, etc.) for Python >=3.7

[ReggX]

Hey there,

I needed to make some changes for a private project of mine.

What began as a small set of changes to conform to mypy --strict ended up in a complete overhaul of the project, implementing more of PyAutoGUI's functions directly into pydirectinput and extending function signatures with optional keyword-only arguments.

Your welcome to take the changes and integrate them upstream, there are some pitfalls though:

The whole package is in-line typed, which means it will need at least Python 3.7 to run. It's also modifying the README to match my forked pypi package that I use for other stuff, so it can't be merged as is. It is on a seperate branch, so you're free to modify it before merging.

Please let me know if you're interested in merging this.

(Had to redo #36 because I accidentally removed the branch)

[Someone45]

This is really awesome! Good stuff :D