iClass support

[nvx]

Requires enabling in Makefile and disabling other options to fit in program space below 64k. An example Makefile with iClass support enabled that fits is at https://github.com/nvx/ChameleonMini/blob/proxgrind/Firmware/Chameleon-Mini/Makefile

Note that apps don't seem to support this new unknown type very well (the Android app just flat out refuses to load the file, while ChameleonMini-rebootedGUI defaults to MIFARE) and will require updating. I've updated the latter here nvx/ChameleonMini-rebootedGUI@38af56d (unknown file types now leave the type unchanged by default too which is handy for adding new formats generally), but it doesn't look like the Android app is open source though so not sure how one would go about getting that updated.

[nvx]

As an aside, when building the firmware ensure the program size reported at the end of the build is below 65535. While this is only ~50% of the space, it looks like the remaining space is reserved for holding card data so bad things happen if the code goes above that point. I'm not sure how much of the space above 64k is being used and if it could be tweaked to be slightly smaller to allow more options to be enabled at once.

Whatever the threshold has to be, it would also be nice if the build process detected overrunning the program space automatically to fail the build. I'm sure it'd save a lot of confusion with newcomers.

[iceman1001]

Awesome contribution,
and yes, the build should preferably detect and warn when building a too large image.