reserve border when full screen

Signed-off-by: Tan Wei <weix.z.tan@intel.com>
move all to cmd/twwm/

Signed-off-by: Tan Wei <weix.z.tan@intel.com>
export pulsechan

Signed-off-by: Tan Wei <weix.z.tan@intel.com>
add twwm-ping

Signed-off-by: Tan Wei <weix.z.tan@intel.com>