Favorites System

[davocarli]

What's changed?

This PR lays the groundwork for a favorites system powered by a favorites.ini in the universal library, then implements it in the Wood theme (the theme I use).

Universal Groundwork:
favorites.cpp lives in an opt-in source directory, to be reused across themes. It provides get/toggle functions plus a flag to indicate whether the last launch happened from favorites intended to be consumed on boot to restore the view. favorites.ini stores the full paths of favorited files as a '|'-separated list (: is used elsewhere but cannot be used with full paths because of the sd:/ and fat:/ prefixes).

Wood Theme Implementation:

• A "*Favorites" folder appears at the card root, only when at least one favorite exists. "*" was chosen because it cannot be used in FAT directories so it won't ever interfere with a real folder.
• Favorite status is toggled from the Y-menu per-game settings.
• Interacting (launching or Y-Menu) with a game in the favorites view is done by performing a temporary chdir to the game's real directory, then restoring the previous directory as-needed.
• Favorites whose file no longer exists are removed from the ini on load.
• The "remember last position" setting correctly reopens the favorites view by setting/checking the LASTVIEW flag in the ini.

Where have you tested it?

melonDS in DSi mode, on a physical New 3DS XL running off the SD card, a physical DSi off the SD card, and on a DS Lite with an R4 clone cart from r4dsll.com. Built with the repo's Docker image.

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Pull Request status

• This PR has been tested using the latest version of devkitARM and libnds.