add clear/play button
make title be an inline-block and have a thiner font
toggle to change status
make toggle button work successfully
send initial data when socket is opened
draw the initial data when socket is opened
send status message to server
add status support
send clear signal to server
clear data when receive clear signal
Merge branch 'feature/button-control' into develop
update preview image
update changelog
update version number
Merge branch 'release/v0.4' into develop