* Add babel-plugin-syntax-typescript and babel-plugin-transform-typescript
* Add babel-preset-typescript
* Remove unnecessary handler for JSXOpeningElement
* Use `t.isFoo(node)` instead of `node.type === "Foo"`
* Clean up parameter property assignment generation
* Don't use function for `isSuperCall`
* slice -> shift
* Calculate sourceFileHasJsx only if necessary
* Remove `export =` support
* remove some syntax readme newlines [skip ci]
