Updated Language Service API.

* Updated Language Service to Microsoft/TypeScript@6287efc24de2113c0e6e9b8caea7f179c0e11af2 with corresponding API changes.
* Removed typescriptServices.js from bin/main.js and bin/worker.js bundles, loading dynamically instead.

New API is unstable as it's part of new compiler rewrite, but might be useful to start migrating to it as earlier as possible since it breaks compatibility for older code.