Add support to handheld mode

[lbsbezerra]

Hello Banz99! The Skyward Sword toggle worked flawlessly here, such a small change that made a huge difference for this game!
Quick question: Is it possible through Mission Control to add this toggle option if you're playing with the Joycons in handheld mode as well? Or because the Joy-Cons are attached to the Switch, they may be considered "USB" and something like "sys-con" should change its values so I can "toggle" through it?

I don't know if you have any answers about that, but even if you don't, if you can at least show me what changes you did to make the L button toggle, I can try to fork sys-con and take a look at this thing by myself!

Thanks!

[Banz99]

You can see my code in the SkySwoSwapL branch here (the whopping amount of two commits...), as for the rest, having talked to Ndeadly himself, sys-con doesn't handle the joycons on the rails, that is relegated to a uart interface that would need a reimplementation and as you can probably imagine, there are no current plans for that. Thing is, this entire thing is an ugly hack at best, you may expect something similar but much more in depth (turbo buttons, button combos, etc) to be integrated at some point in the main project.