Serpentai

* FIX - emptied out __init__.py for serpent.input_controllers (AKA win32api trying to import on Linux)

* MAJOR CHANGE - added a KeyboardKey enum containing all valid keys that can be pressed on a standard keyboard; all InputController methods that accept keys now require KeyboardKey items
* FEATURE - added a fully-compliant native Windows input controller that uses the SendInput DLL function
* FEATURE - added 'move', 'click_down' & 'click_up' to the InputController protocol; implemented them in PYAUTOGUI & NATIVE_WIN32
* FEATURE - context classifier validation during training can now be skipped
* FEATURE - context classifier model checkpoints can now be autosaved
* FEATURE - locate() from the SpriteLocator can now use screen regions
* FIX - prevented an empty list to get to a min() call in locate_string

* FIX - macOS frame reshape error should be resolved; Including the top bar as part of the capture until someone can a programmatic way to get the inner window size.
* FEATURE - added a Web Browser GameLauncher for people who want to tackle web games
* FIX - Added a default static seed to the the training of the context classifier dataset split operation

* REFACTOR - InputController now pivots on a backend to allow extension; PyAutoGUI extracted to a backend (default)
* FIX - no CUDA initialization unless it's actually needed
* FEATURE - new `serpent window_name` command to assist in finding the proper kwargs["window_name"] for Game plugins
* FIX - stopped initializing a VisualDebugger instance on every new GameFrameBuffer. Huge performance gain in frame consumption rate.

* FIX - DarwinWindowController is_window_focused should use process title and not name

* FIX - initial applescript to find focused windows was fine but macOS users need to use process name and not the window name