I don't think we need the extra bin folder; we should be
able to declare our types all in index.d.ts.
This also checks in the package-lock.json, now that we
have devDependencies to run those type checks.
`make typecheck` runs the typecheck tests.
The tsconfig.json and tslint.json were created following
the instructions at https://github.com/microsoft/dtslint
and using the DefinitelyTyped rules.
Bug: skia:10717
Change-Id: I7f943e9cfa264496e0d8932018ab1749702ab2c4
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/322957
Reviewed-by: Nathaniel Nifong <nifong@google.com>
df47abcbb9