Typescript type definition

[yxliang01]

Typescript is getting popular nowadays. In order for projects making use of this project getting benefits from the typing, a type definition is necessary for this library. This issue is to track the progress of such effort. There are already efforts on creating types for this library at https://github.com/DefinitelyTyped/DefinitelyTyped/tree/master/types/solidity-parser-antlr . However, after discussion at #47 , we think that having type definition in this repo is more preferable.

CC all authors of the created types at @ type: @LogvinovLeon @albrow @yxliang01

Tasks

1. Port latest typing definition from @type : feat: add typescript types #49
2. Introduce linting for the typing files
3. Test cases for the types to make sure the implemented library has interface same as the defined type: types(index.d.ts): improved the type definitions #52 and more to happen
4. Finish the typing for the current master version (some issues tracking in detail: UnaryOperation expression type missing from type definitions #86 NewExpression expression type missing from type definitions #87)