Modify pcsc.c and mifare.c files.
1. add code into pcsc.c to have support Mifare classic card.
2. The PCSC reader has SW value, add response data length for PCSC
reader
1. Modify pcsc.c code, add R502 and bR500 support into PCSC driver
2. Update readme, tell user how to build with pcsc driver
3. Add FAQ for bR500 and R502 in readme