Use customized command string in scons
Rename `--default-comstr` to `--verbose`
Merge pull request #17 from rogerz/master

Customize command string in scons
Add detail build result
Use build matrix
add all arm bsp to build matrix
Remove unsupported BSP
Fix build error in efm32
Merge pull request #24 from rogerz/auto-ci

Add all arm bsp to building matrix
Merge pull request #25 from rogerz/build-error

Fix build error in efm32
rewrite serial/uart code in simulator to support multi-uarts
fix bug in simulator/drivers/serial.c which deadlock may happen if multi-uart both output use printf
clean code in simulator/drivers/serial.c
add declaration in simulator/drivers/usart_sim.c