MifareCard NDEF read/write don't work on multi-application cards

[jdbruner]

In the MifareCard class, WriteNdefMessage and TryReadNdefMessage have two issues:

1. They assume that the entire card is available for the NDEF message. A multi-application card could use some portion of the memory for other purposes. They should consult the Mifare Application Directory in sector 0 (and, for 2K and 4K cards, sector 16) to find the range of contiguous sectors that are assigned to the NDEF tag.
2. They do not account for the larger sector size in the second half of 4K cards. (The first 32 sectors have 4 blocks per sector; the last 8 sectors of a 4K card have 16 blocks per sector.)