Merge pull request #82 from shengwen1997/master

Fix the PWM  issue (#81)
Remove the ps command
Remove the display command
Merge branch 'master' of https://github.com/shengwen1997/QuadrotorFlightControl into watch_cmd_experiment
Rename the module "board" to "led"
remove the useless file "stm32f4_system.c"
delay: Remove some Chinese comments
Move all files from "module" to "driver"
Move the USART3_IRQHandler function from "interrupt.c" to "serial.c"
remote_control.c: rearrange the code
Move the structure "serial_msg" form "global.h" to "serial.h"
Add two visual mode for the gdb
Merge branch 'master' of https://github.com/shengwen1997/QuadrotorFlightControl into watch_cmd_experiment
Merge branch 'master' of https://github.com/shengwen1997/QuadrotorFlightControl into watch_cmd_experiment
Fix duplicate name
Change naming style(type more faster)
Merge pull request #83 from shengwen1997/master

Watch Command Implementation
Merge pull request #90 from moon-bear/watch_cmd_experiment

merge minor change in watch command
Merge pull request #84 from shengwen1997/ps_remove

Remove the PS Command
Merge branch 'gdb'