Merge pull request #884 from pwpiwi/fix_iclass_snoop

* determine and write meaningful times into trace
* code deduplication: use ISO15693 snoop function
* speed up SnoopIso15693(), reduce DMA buffer size
* add jamming option '-j' to 'hf iclass snoop'
* fix issue #882
* whitespace fixes
* make room for one more bit for FPGA minor mode
* new mode FPGA_HF_READER_MODE_SEND_JAM
* implement jamming in Handle15693SampleFromReader