Bug in package tests: ReferenceError SimpleSchema is not defined

```
ReferenceError: SimpleSchema is not defined
at Package (validated-method-tests.js:3:17)
at C:\Tech\escalade\profile-meteor\.meteor\local\build\programs\server\packages\mdg_validated-method.js:366:4
at C:\Tech\escalade\profile-meteor\.meteor\local\build\programs\server\packages\mdg_validated-method.js:375:3
at C:\Tech\escalade\profile-meteor\.meteor\local\build\programs\server\boot.js:242:10
at Array.forEach (native)
```

Environment:
Meteor 1.2.1
validated-method 1.1.0
simple-schema 1.5.3 (as an explicit dependency of the project)

Steps:
1. Take an old project, and install validated-method
2. Convert a vanilla Meteor Method to a validated-method
3. Run the project

I have SimpleSchema being used for validation in all the Template js files, so it is generally available to app code. This is Meteor 1.2.x, so all the code is eager-loaded and available everywhere. I'm guessing this has something to do with the fact that the error is from a package, so presumably the load order means that validated-method is getting loaded before simple-schema is available.

Start with validated-method-tests.js at the failing Package entry point and inspect how simple-schema is declared and loaded for package tests. Reproduce the failure with Meteor 1.2.1, validated-method 1.1.0, and simple-schema 1.5.3; done means the package starts without the ReferenceError and its tests pass.

Written by the indexing model from the issue text.