Chinese localization

- [x] Controls: @yiting 
- [ ] Sprites
- [ ] Music
- [ ] Sound
- [ ] Arrays
- [ ] Boolean
- [ ] Canvas
- [ ] Color
- [ ] Images
- [ ] Math: @whleung 
- [ ] Random
- [ ] Vectors
- [ ] Objects
- [ ] Strings
- [ ] Paths
- [ ] Points
- [ ] Rects
- [ ] Sensing
- [ ] Motion
- [ ] Shapes
- [ ] Geolocation
- [ ] Sizes
- [ ] Text
- [ ] Matrix

Related to #690.