Updated libopencm3. Disabled lpc43xx examples.

We merged a huge patchset for lpc43xx that breaks the examples. As we
are waiting for those to be updated it is better to disable the
automatic build of them.
stm32f3discovery examples added.

- miniblink
- button
- fancyblink
- adc
- Non tested yet! But they compile.
stm32f3discovery ld script corrected as recommended in #82.
Flashing now using openocd. GDB Debugging possible and tested :).
Adc example fixed (printing garbage before) and cleaned.

- Integer printing function fixed.
  	  - because of comparison against smaller than 0 numbers we must use signed numbers!
	  - Value zero was not printed at all.
	  - It was printing one more character than it should.
- Erasing unnecesary commentaries.
- Erasing debugging help.
stm32f3discovery: Adding i2c accelerometer example.
stm32f3discovery: Moving read and write convinience functions to libopencm3.
stm32f3discovery: spi l3gd20 example added.
stm32f3: cdcacm example added and tested.
stm32f3: Examples Makefile now includes f3 dir.
stm32f3: cleaning some unused variables.
[STM32F3] Updated locm3 so that the newly added f3 examples compile.
Global: Remove temporary backup files

file.c~ (note the tilde at the end) are temporary backup files used by some
editors. They are not needed.

Signed-off-by: Alexandru Gagniuc <mr.nuke.me@gmail.com>
[lm4f] Added a note for Windows users to the README
[stm32x] Use modern header include paths.

Replace includes of stm32/YY/xxxx.h with stm32/xxxx.h
Replace stm32/YY/nvic.h with cm3/nvic.h.
In some cases, the include list was resorted alphabetically when it was
complicated and I was reviewing them manually, but most of this was
automatically done.
[BUILD] Paralelize cleaning of examples

make clean     1:50 -> 1:55 (no change)
make clean -j8 1:30 -> 0:28 (strongly faster)

Measured on Core i7 (4 cores, each HT) @ 3GHz
Fix broken adc.h includes

My bad, I'd been testing my header includes against a branch with some
draft unification of the adc code.  ADC is one of the remaining major
peripherals that isn't unified neatly.
Update to latest libopencm3

And fix traceswo to match api change upstream.
Updated USB HID examples with HID descriptor comments
Updated libopencm3 submodule to the newest version.