Duplicate model creates a confusing error

[davemackintosh]

Versions

What is the output of:

1. multicolour version latest/all
2. node -v 7.x
3. npm list --depth=0

Expected behavior

Helpful error message explaining that a blueprint with the name device.js is overwritten with a confusing error by another model named devices.js

Message along the lines of "We noticed you have two models that compute to the same name, the blueprint with the lowest alphabetical order will override the others. Exiting"

Actual behavior

Cannot convert null or undefined to object.

Steps to reproduce behavior

Create a blueprint named device.js with a correct definition. Create a blueprint named devices.js which returns a list of device.js

Error...