Bring the support for STM32 F3 Discovery board (ARM Techcon 2012)

Support was tested by attaching USB cable to USB ST-LINK USB port, starting

	./st-util

Which resulted in proper device recognition:

	2012-11-03T23:11:25 INFO src/stlink-common.c: Device connected is: F3 device, id 0x10016422
	2012-11-03T23:11:25 INFO src/stlink-common.c: SRAM size: 0xa000 bytes (40 KiB), Flash: 0x40000 bytes (256 KiB) in pages of 2048 bytes
	Chip ID is 00000422, Core ID is  2ba01477.

Then from GDB, after "target remove localhost:4242", I tested reads:

	x/w 0x20000000

And writes:

	set {int}0x20000000 1

And ELF loading:

	(gdb) load main
	Loading section .text, size 0x10 lma 0x20000000
	Start address 0x20000000, load size 16
	Transfer rate: 410 bytes/sec, 16 bytes/write.

And verified dissasembly (in my case--with Thumb mode) with objdump -d <elf>
output:

	(gdb) set arm force-mode thumb
	(gdb) x/7i 0x20000000
	=> 0x20000000:	push	{r7}
	   0x20000002:	sub	sp, #12
	   0x20000004:	add	r7, sp, #0
	   0x20000006:	ldr	r3, [r7, #4]
	   0x20000008:	add.w	r3, r3, #1
	   0x2000000c:	str	r3, [r7, #4]
	   0x2000000e:	b.n	0x20000006