Virtual keyboard support, control improvements, cutscene audio

[rsn8887]

This PR includes the following fixes

• fix right stick click. It can now be used also to push buttons on the panel. Coincidentally, this allows right stick click to skip the intro, too!
• implement virtual keyboard support (name entry, etc.). The keyboard opens at the same time when SDL_StartTextInput is called in the code.
• fix horizontal scrolling of automap with right stick
• implement proper radial deadzones for analog sticks
• use only SDL for joystick axis handling (removes libnx dependency in event handling code)
• fix cutscene audio

Closes #5

[rsn8887]

Tested and ready to merge.

[rsn8887]

Tested keyboard etc.

Ready to merge @lantus :)

[rsn8887]

Ok tested and ready to merge again.

[lantus]

testing now.

[rsn8887]

I got cutscene audio to work one sec

[rsn8887]

Ok I just tested it with the new cutscene audio fix. Works fine.

[rsn8887]

I made another change with cutscene audio. In the case the audio device would fail to open for a cutscene, it could have crashed, but not anymore.

I think this is complete now. Ready to merge.

[AJenbo]

Nice job getting things cleaned up, I think we can start working on upstreaming things once this is merged.

[rsn8887]

It should work fine on other devices I think. I don't think there's any harm in some additional Mix_CloseAudio() and Mix_OpenAudio() calls, but I only tested it on Switch.

Has cutscene audio been a known bug on other devices, too?

[AJenbo]

Haven't had issues, but this looks reasonable, honestly i was surprised it wasn't needed. on other devices

[lantus]

Looks good. Merging