Add dependency on montage/test for mocks

We haven't moved this into montage-testing because we're not satisfied with the current API. 
We need to use it nonetheless, hence this hack.
Upgrade to specialize/constructor/new/super
Remove String.isString usage
Revert "Remove problematic content property from list blueprint"

This reverts commit 70341293b9a7286b535d4155c8c43380c264827d.
Correct details for publishing
Add repository to package.json
Remove radio-button-group dependency
Fix syntax error on video player test
Graduate to 0.1.1