Uses config API instead of bower.json

This swaps out all the references to `this.cpui.paths` to use `this.generator.get('path')`. We're also setting up a default config so that if any of the keys (or the entire `.yo-rc.json` file is missing), the defaults will get injected instead. 

- [x] If I create anything with an already existing module, it exits as soon as I've named the module. I haven't figured out the cause of this one yet.
Might just be safest to have this in the module's directory as `defaults.json`, so further changes to the defaults don't require traipsing through the code. You can use `JSON.parse(this.readFileAsString('name-of-file'))` to read a file in from disk as JSON.