This PR adds the ability for VS Code Web to load javascript/typescript types from both dependencies, and through ATA.

• initial proof-of-concept with loading node_modules-based types on sample project
• figure out correct way to read workspace files relative to requested node_modules files (see TODOs loading package.json/lockfiles)
• get node_modules/ type loader to work in typescript files, too, in both inferred and .tsconfig.js projects (???)
• Figure out wtf is going on with the random errors that are happening on web with things not being iterators (I think this is just a vs code web bug?? but it breaks everything??)
• initial prototype of web-friendly implementation of TypingsInstaller
• Set up node-maintainer as a "proper" dependency once it starts getting published to NPM, instead of vendoring it.
• Skip restoring typescript lib packages?
• Make sure stuff works right in more complex multi-project workspaces. node-maintainer doesn't support workspaces (for now), but we can get a similar effect by having one maintainer per package.json
• Figure out why ATA doesn't kick in unless I close a .ts file first???
• Figure out why Go To Source Definition for non-module targets isn't working
• Add localStorage (or such?) support for caching previously-loaded typings
• Figure out story with CORS, esp for private registries.
• Fix file watching to make sure stuff gets updated on package.json edits (Note: will probably need to work with Nathan on this. idk what's going on with watching in general)
• Case sensitivity control?