merge
Merge branch 'master' of https://github.com/th365thli/SLogo
Merge branch 'master' of https://github.com/th365thli/SLogo
Merge branch 'master' of https://github.com/th365thli/SLogo
Merge branch 'master' of https://github.com/th365thli/SLogo
implement a lot of required commands. fixed some bugs
Merge branch 'master' of https://github.com/th365thli/SLogo