Allow for modules without exports

They are undefined, so the seen[name] test would previously fail.
Merge pull request #357 from joliss/loader

Allow for modules without exports
Latest grunt-ember-templates uses NPM package deps

This allows us to specify the specific versions of
`ember-template-compiler` and `handlebars` that our applications need
directly in our `package.json`.
Merge pull request #358 from rjackson/use_packages_for_template_compiler

Latest grunt-ember-templates uses NPM package deps
support for emberscript
Merge pull request #362 from ghempton/emberscript

support for emberscript
WIP
WIP