4.0.0

• Update existing core components and API to 4.7.1
• Update existing lab components to 4.7.1
• Update icons (add 4500 more, including proxies)
• Promote some components from lab to core
• Add MuiTheme types and providers
• Add style API (createGenerateClassName, styled, withTheme)
• Expose styles for core and lab components
• Add color manipulation API / tools
• Add CI to test compilation of all components
• Add ButtonGroup component
• Add Container component
• Add TextareaAutosize component
• Add Autocomplete component (lab)
• Add Rating component (lab)
• Add Skeleton component (lab)
• Add TreeView / TreeItem components (lab)