1.2.0: Halp plz

We all make mistakes. Given that, wouldn't it be nice if your patternlab-node engine would actually try to tell you what kind of mistake you made, and look good doing it?

I think so too.

• if a requested pattern partial is missing, say so; if there's compilation error, print the output from the exception.
• if you've tried to call a non-existent pattern with _.renderNamedPartial('atom-not-there', obj), say so in the error message
• beautiful and helpful error reporting during underscore template rendering
• Shift template compilation time to the partial registration phase