* check if an nds save file can be opened for writing
also add the ability to open a file in append mode
* fix multi-instance saves
also move the check for file writability into a separate function (probably uneeded?)
* implement check for gba roms
* move rom load error messages into the functions
also finish gba slot (oops)
* improve error string
* check write perms before saving path settings
* fix memory leak
* check for writability of firmware/nand/sds
* add secondary checks for nand/firmware
* add check for config file being writable
* Return the file write error as a QString to avoid the invalid char*
causing a garbled error message.
Qt wants it as QString either way.
* Reload the SD card for `CartSD` and all subclasses
* Make `ROMManager::LoadDLDISDCard` delegate to `GetDLDISDCardArgs`
* Add a method overload for `CartSD::SetSDCard`
* Initialize new SD card images with the correct size
* Sync the old card to the host (if applicable) when move-assigning a new one
* Only sync the old card to the host if it's not read-only
* Remove static state in `FATStorage`
- Replace `FF_ReadStorage` and `FF_WriteStorage` with lambda functions
- Keep open and use the single `File` handle throughout the `FATStorage`'s life
* Simplify the SRAM's representation in `NDSCartArgs`
- I overthought this one.
- I could've just checked `args && args->SRAM`, but then some other poor bastard might make this mistake.
- Don't mix `pair`, `optional`, and `unique_ptr` all at once, kids.
* Fix a `nullptr` read
* Fix detection of native NDS ARM BIOS images
- Instead of checking for built-in BIOS images, now the altered methods check for native ones
- The CRC32 must match exactly; patched BIOS images will result in `false`
* Encapsulate `NDS::ARM9BIOS` and `ARM7BIOS`
- Also compute the checksum only when setting the BIOS
* Allow 3D renderers to be created without passing `GPU` to the constructor
* Make the initial 3D renderer configurable via `NDSArgs`
* Fix a compiler error
