Tengo V2

Changes

• switch-case statement
• variadic function arguments
• better error handling
• better documentation (e.g. full language specification)
• more builtin modules (stdlib) with more scalable approach
• smaller runtime size (e.g. remove stdlib packages)
• more efficient implementation for immutable array/map
• Script inputs and outputs explicitly defined at language level (maybe force moduling)
• better package naming: simple names such as script and compiler conflicts with package names