Allow use of keyboard for control in sim

[TheFlameFish]

Using sim to develop without a real robot is currently difficult, as it requires an Xbox controller.
This PR adds a boolean in constants titled useKeyboard. If useKeyboard is true and currentMode is SIM, use keyboard bindings instead of Xbox controller bindings.
Tested in sim with changes on #17.

[nolanhergert]

I understand making a default keyboard map, which I assume simgui-ds.json is doing. Can you confirm?

However, I hesitate forcing it on by default. What if a someone does have an XBox controller? What is inconvenient about the current method of dragging the joystick/keyboard on the Sim GUI?
https://docs.wpilib.org/en/stable/docs/software/wpilib-tools/robot-simulation/simulation-gui.html#adding-a-system-joystick-to-joysticks

[TheFlameFish]

I understand making a default keyboard map, which I assume simgui-ds.json is doing. Can you confirm?

However, I hesitate forcing it on by default. What if a someone does have an XBox controller? What is inconvenient about the current method of dragging the joystick/keyboard on the Sim GUI? https://docs.wpilib.org/en/stable/docs/software/wpilib-tools/robot-simulation/simulation-gui.html#adding-a-system-joystick-to-joysticks

Yes, simgui-ds.json sets the keybindings for keyboard 0 to match the axes and buttons of an Xbox controller.

In my testing, dragging the keyboard to the joystick 0 slot doesn't work. I think the XBoxController class doesn't accept keyboard even if its bindings match an XBox controller. I also expect we'll be using sim without an Xbox controller on hand more frequently than with one.

[Ace5tar]

i dont see an issue merging this, but i do want to comment that configuring a keyboard control scene in sim gui is very trivial, so this may be an overcomplication

[TheFlameFish]

On my computer (MacOS), the keyboard sim control (as described in docs) does not seem to work with the XboxController class. With joystick 0 being set to keyboard 0 and with the keybindings being set to match the inputs of an Xbox controller, all keyboard inputs are ignored by the simulated robot. Do other devices behave differently in this regard?

[nolanhergert]

Were you unable to find something that detected if an XBox controller was connected?

[TheFlameFish]

Yes, I think the CommandXboxController.isConnected method will work.