add Stm32f3 std lib
refactor stdlib handling

Signed-off-by: Stefan Guelland <stefan@sguelland.de>
add Stm32F3Discovery board

Signed-off-by: Stefan Guelland <stefan@sguelland.de>
add stm32f10x

Signed-off-by: Stefan Guelland <stefan@sguelland.de>