Add tests for bonfire config concerning appName

[ahouchens]

Closes #5

[vine77]

Thanks for adding tests. However, this looks like you're asserting that the config values must always be present, when in reality we want bf-header to work with our without them in the consuming app's environment.js. And you might as well leave 'it renders'.

[ahouchens]

This is where we may have confusion. I have the understanding that not all unit tests need to pass. These unit tests are for the cases for defining the config values if that functionality is desired.

I will add 'it renders' back in for a test case in the dummy app - good point.