Added STM32 project.
 Changes to be committed:
	new file:   STM/codec.c
	new file:   STM/codec.h
	new file:   STM/main.c
	new file:   STM/main.h
	new file:   STM/startup_stm32f4xx.c
	new file:   STM/stm32f4_discovery.c
	new file:   STM/stm32f4_discovery.h
	new file:   STM/stm32f4xx_conf.h
	new file:   STM/stm32f4xx_it.c
	new file:   STM/stm32f4xx_it.h
	new file:   STM/system_stm32f4xx.c
	new file:   STM/usb_bsp.c
	new file:   STM/usb_conf.h
	new file:   STM/usbd_conf.h
	new file:   STM/usbd_desc.c
	new file:   STM/usbd_desc.h
	new file:   STM/usbd_usr.c