Rework ethernet to module as USB, working transmit
Ethernet transport layer working. Added checksum offload configuration
Rework ethernet to module as USB, working transmit
Merge branch 'ETH-regs-F4' of ssh://github.com/BuFran/libopencm3 into ETH-regs-F4

Conflicts:
	lib/stm32/f4/Makefile
Style corrected, Buffer Descriptor accesses are now macro-like
remove unnecessary typedef