We should be using both "error" and "warn"

[samhstn]

For instance, when I am doing some code rearranging and trying get my code back to a working state, when I run the goodparts executable. I want to ensure that the code is not going to error. I don't want to get "error" messages about 'defined but never used', 'complexity', 'trailing whitespace' or 'missing semis'.

So I have to sift through all the "errors" for what I would consider actual errors like 'not defined' or 'unexpected tokens'

@nelsonic @SimonLab @jrans @eliasCodes Thoughts?