Add libopencm3 submodule
Build against libopencm3 submodule tree by default
usb: Rework configuration change notification
Bump libopencm3
Fix NVIC interrupt macro names

In libopencm3 master the NVIC macros are prefixed with NVIC_ not
NVIC_M4_
Ensure that LPC43XX is defined for libopencm3
A few more changes due to the libopencm3 merge
firmware/: Use uint32_t instead of u32
firmware/: Update #includes for libopencm3 merge
Bump libopencm3
doc: block diagram of HackRF

Source: http://2013.hackitoergosum.org/presentations/Day2-04.HackRF%20A%20Low%20Cost%20Software%20Defined%20Radio%20Platform%20by%20Benjamin%20Vernoux.pdf
Merge pull request #100 from jboone/master

Incorporate bgamari changes for libopencm3 upstream.
Merge pull request #98 from mikeryan/blockdiagram-images

doc: block diagram of HackRF
HackRF One: started hardware design by copying Jawbreaker
removed boot headers, added reset and DFU pushbuttons
removed some DNP parts and 0 ohm resistors
removed USB LEDs
removed U3 test points (there is another UART exposed on the ISP header)
fixed VCCIO1 to VCC
fixed MAX5864 OVDD to VCC