add stmf4 chip and try xmega event system ring

gpio/stm32f407/ide.jpg

gpio/stm32f407/index.html

gpio/stm32f407/scope.jpg

gpio/stm32f407/setup.jpg

gpio/stm32f407/stm32-register-help.pdf

ring.json

wildwest/xmega-eventsys/index.html

...ys/xmega-eventsys-ring/.vs/xmega-eventsys-ring/v14/.atsuo

...ga-eventsys/xmega-eventsys-ring/xmega-eventsys-ring.atsln

...ys/xmega-eventsys-ring/xmega-eventsys-ring/Debug/Makefile

...tsys/xmega-eventsys-ring/xmega-eventsys-ring/Debug/main.d

...tsys/xmega-eventsys-ring/xmega-eventsys-ring/Debug/main.o

.../xmega-eventsys-ring/xmega-eventsys-ring/Debug/makedep.mk

...ys-ring/xmega-eventsys-ring/Debug/xmega-eventsys-ring.eep

...ys-ring/xmega-eventsys-ring/Debug/xmega-eventsys-ring.elf

...ys-ring/xmega-eventsys-ring/Debug/xmega-eventsys-ring.hex

...ys-ring/xmega-eventsys-ring/Debug/xmega-eventsys-ring.lss

...ys-ring/xmega-eventsys-ring/Debug/xmega-eventsys-ring.map

...s-ring/xmega-eventsys-ring/Debug/xmega-eventsys-ring.srec

...a-eventsys/xmega-eventsys-ring/xmega-eventsys-ring/main.c