Port language server implementation to TS 2.0

[mjbvz]

Debt Item for Nov/Dec

I'm not sure, but this work may have already been completed: microsoft/vscode-languageserver-node@d0dddc1

@dbaeumer Can you please add some more context to this issue. Is https://github.com/Microsoft/vscode-languageserver-node/ the correct code, or does this item target something else?

[dbaeumer]

@mjbvz this has nothing to do with the TS server in general. I should own that item. It is about a library that currently uses TS 1.8.10 to use 2.0.

[dbaeumer]

This is now available in the 3.0.1-alpha releases of the library.