- Fixes cargo publish on deno_typescript, deno_cli_snapshots, and
  deno_cli.
- Combines cli_snapshots and js into one directory.
- Extracts TS version at compile time rather than runtime
- Bumps version awkwardly - it was necessary to test end-to-end
  publishing. Sorry.
- Adds git submodule deno_typescript/typescript

Instead of using core/snapshot_creator.rs, instead two crates are
introduced which allow building the snapshot during build.rs.

Rollup is removed and replaced with our own bundler. This removes
the Node build dependency. Modules in //js now use Deno-style imports
with file extensions, rather than Node style extensionless imports.

This improves incremental build time when changes are made to //js files
by about 40 seconds.