misalignment between code and doc

Hi,

The first issue is

For the AWS Cognito examples using lambda, it is said in doc to use the following env variable:
`BOX_PRIVATE_KEY_PASSPHRASE = `

but the lambda code is using `BOX_PRIVATE_KEY_PASSWORD` (see https://github.com/box/samples/blob/cognito_integration/box-node-cognito-lambdas-sample/tokenExchange/box-manager.js#L16)

The second issue is with the angular2 application

Its mentioned to add a custom attribute called `custom:box_appuser_id` which will store the box id for the given account.

but the application is using `box_appuser_token` (see https://github.com/box/samples/blob/master/box-aws-cognito-angular2-skeleton-app-sample/src/app/config/box/box.config.ts#L10)