Use TypeScript as a package dependency

[ashwinr]

Right now, it's a git submodule. Make it an npm package dependency instead.

[ashwinr]

Okay, so I investigated this some more. The TypeScript npm module has not been correctly implemented. It exports nothing, and so cannot be used in its current form. The other npm modules that depend on it use a hack: they load and execute the file typescript.js (from the installed package in node_modules) into the node VM, which creates a global TypeScript variable.

For now, this is not the right way for tslint. When the npm issue on TypeScript gets resolved, we'll immediately adopt it. It'll make our compilation much faster.

FYI: @derekcicerone