Remove printf testing function
Shell: create the prototype function of the watch "command"
Makefile: Fix the target "gdbauto" with the -tui argument
Block the Barometer related code
Arrange the code of the task creation
Let the watch command reading for the interruption signal
Fix the wrong barometer blocking issue
Merge branch 'watch'

Conflicts:
	program/shell/shell.c
Shell-watch :port the gui command into the watch task
Merge branch 'master' of https://github.com/shengwen1997/QuadrotorFlightControl
Empty the motor value while the safty button is turning on
Rename the name of global variable array
Rename the member name of global_struct
Rename the structure "global_struct" to "global_t"
Add new type "pwm_t" and "attitude_t"
Rearrange the code
Create new type "status_t" to replace the type "SYS_STATUS" and "SD_STATUS"
Create new type "system_t"
Move the "global_var" into the structure "system" and rename to "variable"
Replace the variable "sys_status" with "system.status"