fix 'hf iclass sim':

* chg to reader command decoder in iso15693.c (require no modulation before SOF)
* add 'has_been_low_for' logic to hi_simulate.v (same as in other FPGA modes, default to "no modulation")
* add simulation of chip status (IDLE, ACTIVE, SELECTED, HALTED)
* check ACSN on SELECT
* add simulation of RESELECT
* always check length of reader commands
* fix printing of NR, MAC in sim 2 mode
* fix response length to CHECK command