Merge pull request #42 from TitanMKD/master

Added hackrf_transfer option -w to receive file with Wav/RIFF Header and automatic name compatible with SDR# IQ file(*.wav)
exit when failing to transfer
Merge branch 'master' of git://github.com/mossmann/hackrf
Lot of comments added.
sgpio_if (top.vhd) CPLD VHDL fix for IQ/aliasing problems for ADC. (cpldjtagprog => sgpio_if_xsvf.h updated to rebuild).
usb_performance.c SGPIO IQ fix for ADC (QI->IQ) for new CPLD (use usb_performance_rom_to_ram version else there is some packet lost even at 10Mhz sampling rate => make -f Makefile_rom_to_ram.)