Release sketch v1.1.0

This is a major release. Here is a list of major improvements (from v1.0.3):

• Add WebSocket for R-JavaScript interop (i.e. R functions and packages can be used)
• Add support to transpiling error handling keywords
• Switch from a mixed S3-R6 OOP to pure R6 OOP
• Add safeguard to perform pre-transpilation check automatically
• Support per-file transpiler configuration
• Optimise transpiler performance (>100X faster for large files)
• Add "testthat" module for testing sketch applications
• Add support to loading resources from Content Delivery Network (CDN) (10~100X smaller file size)