Add TI-Nspire support

[shezik]

Building and running on TI-Nspire as simulator. Don't know much about Travis CI though.

[github-actions]

	.text	.rodata	.bss	.data	Total (RAM)	Total (ROM)
Base	810040 bytes	441196 bytes	226888 bytes	1776 bytes	228664 bytes	1253012 bytes
Head	810040 bytes	441196 bytes	226888 bytes	1776 bytes	228664 bytes	1253012 bytes
	+0 bytes	+0 bytes	+0 bytes	+0 bytes	+0 bytes	+0 bytes
	+0.0 %	+0.0 %	+0.0 %	+0.0 %	+0.0 %	+0.0 %

[Lauryy06]

Wow, this is great! Can you provide a photo or two to see what it looks like?

[Yaya-Cout]

Why are you building as a simulator instead of a device ?

[shezik]

@Lauryy06 @Yaya-Cout Apologies for not seeing your comments.

Surely I can provide photos! However in its current state, creating a new script will cause Nspire to crash for some reason, and I've been facing a lot of challenges on my schoolwork recently (cheeky you), so I decided to create a pull request and see if anyone else is capable of fixing it.

There are also other problems, such as some colors not showing correctly on Nspire b/w models (maybe a custom skin would help), its keyboard uses 'trig' key to enter sin/cos/tan and is missing dedicated keys, and a sub-menu is required.

The reason for building it as a simulator is that this port is very close to the 3DS port (actually modified on that): they both run on existing host operating systems instead of a bare-bones MCU, as a device would do.

Here are the photos requested.

Don't worry about that school bus yellow. Virginia Beach Public Schools decided they would swap out these for being outdated and I got one from them at a bargain price.

[Lauryy06]

It's really crazy! I'm going to put the pull request in the draft state until everything is finalized, and if I have enough time I'll see if I can fix a bug or two, even though I'm not familiar with this ecosystem and don't have much time available at the moment.
But again what you did is awesome, and I can' t wait to see Upsilon on TI-Nspire!

[Yaya-Cout]

Why do you add <br> ?

Suggested change

	NumWorks est une marque déposée de NumWorks SAS, 24 Rue Godot de Mauroy, 75009 Paris, France.<br>
	Nintendo est Nintendo 3DS sont des marques déposées de Nintendo of America Inc, 4600 150th Ave NE, Redmond, WA 98052, Etats-Unis.<br>
	NumWorks SAS et Nintendo of America Inc ne sont en aucun cas associés avec ce projet.<br>
	NumWorks est une marque déposée de NumWorks SAS, 24 Rue Godot de Mauroy, 75009 Paris, France.
	Nintendo est Nintendo 3DS sont des marques déposées de Nintendo of America Inc, 4600 150th Ave NE, Redmond, WA 98052, Etats-Unis.
	NumWorks SAS et Nintendo of America Inc ne sont en aucun cas associés avec ce projet.

[vanilla-extracts]

The
must be a relic of a mix between markdown and HTML