[Devices] add flags to command

[Skarsnik]

Special flags are just ignored currently x)

[Skarsnik]

Quite low priority with not much application needed that

[jeffythedragonslayer]

Are these the special flags, in Protocol.md?

## Flags

This are the flags you will get from a sd2snes device.

* `FEAT_DSPX` 
* `FEAT_ST0010`
* `FEAT_SRTC`
* `FEAT_MSU1`
* `FEAT_213F`
* `FEAT_CMD_UNLOCK`
* `FEAT_USB1`
* `FEAT_DMA1`

QUsb2Snes add flags to other device since they don't have all the capability of a sd2snes.

* `NO_FILE_CMD` : The device can't perform file operation
* `NO_CONTROL_CMD` : The device can't perform control operation (reset/boot...)
* `NO_ROM_WRITE` : The device can't write to ROM
* `NO_ROM_READ` : The device can't read to ROM

[Skarsnik]

No, it's mostly some special flags you can give to the usb2snes firmware on some commands. It's not really used since only the usb2snes can do something with it.