* fixing hf 15: implement hf 15 snoop
* rename hf 15 record to hf 15 snoop
* speedup sampling / decoding:
* new FPGA mode FPGA_HF_READER_RX_XCORR_AMPLITUDE implements amplitude(ci, cq) on FPGA
* inlining the decoders in iso15693.c
* inlining memcpy/memset in LogTrace()
* giving up the moving correlator for SOF in Handle15693SamplesFromTag
* decode more of EOF in Handle15693SamplesFromTag()
* some refactoring
* added ISO15693 coding for tag messages (CodeIso15693AsTag())
* added ISO15693 decoding for reader commands (Handle15693SampleFromReader())
* send tag inventory response in either high or low speed
* some refactoring and formatting
