Add missing type annotations to avoid typescript compiler errors when 'noImplicitAny' is enabled

[almilo]

TODO:

• Update CHANGELOG.md with your change (include reference to issue & this PR)
• Make sure all of the significant new logic is covered by tests
• Rebase your changes on master so that they can be merged easily
• Make sure all tests and linter rules pass

…pt compiler errors (#132)

[apollo-cla]

@almilo: Thank you for submitting a pull request! Before we can merge it, you'll need to sign the Meteor Contributor Agreement here: https://contribute.meteor.com/

[helfer]

Thanks! I'll merge this and roll a new release tomorrow.

[DxCx]

@helfer it's looks good :)