title: eslint should be listed in the project's dependencies, not devDependencies
body: <p>Either I don't understand <code>dependencies</code> vs. <code>devDependencies</code> in node 100% yet or eslint is just wrong here (not capable of analyzing this correctly):</p>
  
  <pre><code>   3:1   error  'chai' should be listed in the project's dependencies, not devDependencies              import/no-extraneous-dependencies
     4:1   error  'chai-enzyme' should be listed in the project's dependencies, not devDependencies       import/no-extraneous-dependencies
     5:1   error  'enzyme' should be listed in the project's dependencies, not devDependencies            import/no-extraneous-dependencies
     7:1   error  'sinon' should be listed in the project's dependencies, not devDependencies             import/no-extraneous-dependencies
     9:1   error  'redux-mock-store' should be listed in the project's dependencies, not devDependencies  import/no-extraneous-dependencies
  </code></pre>
  
  <p>These are test dependencies, so why is it saying that they should be listed in <code>dependencies</code>?  </p>
  
  <p>Additional note: We're using Travis as our CI so I don't know if it makes a difference for that at all either.</p>